Geometry-dependent monolayers for efficient inverted perovskite solar cells

Geometry-dependent monolayers for efficient inverted perovskite solar cells | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Physical Sciences - Article Geometry-dependent monolayers for efficient inverted perovskite solar cells Chuluo Yang, Suhao Yan, Xiaojun Yin, Bo Xiao, Xuefeng Chen, Jisheng Xu, and 10 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9432790/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Record efficiencies in inverted perovskite solar cells (PSCs) are increasingly depend on precise energetic and electronic matching of self-assembled monolayers (SAMs) at buried interfaces(1-6). Yet most SAM designs address only one dimension of interfacial control, emphasizing either defect passivation at the perovskite contact or work-function alignment at the electrode (7-10). Moreover, hopping-mediated charge transport across the functional monolayer is often overlooked (11-13). Here we establish a geometry-dependent three-layer molecular-contact framework by integrating a multiple-site fixation strategy with fusion-topology reconfiguration of a benzothienocarbazole scaffold, enabling bidirectional anchoring and geometry-tailored frontier-orbital coupling across both interfaces. The resulting interfacial synergy suppresses defect formation, facilitates charge extraction, and therefore delivers a record high power conversion efficiency (PCE) of 28.11% (27.78% certified) in inverted PSCs, while retaining over 95% of the initial efficiency after 1,500 hours aging according to ISOS-L-2 protocol. This work defines a transport-aware, dual-interface-anchored SAM design model that enables the synergistic optimization of interfacial energetics, defect passivation and charge-transfer kinetics within a unified molecular framework. Physical sciences/Energy science and technology/Energy harvesting Physical sciences/Materials science/Materials for devices inverted perovskite solar cells self-assembled monolayer power-conversion efficiency interfacial engineering frontier-orbital coupling Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction With the emergence of self-assembled monolayers (SAMs), the design space of inverted perovskite solar cells (PSCs) has substantially redefined by rendering this buried interface molecularly addressable. 8-10,13-15 As molecularly thin hole-selective contacts, SAMs enable favorable work-function tuning, low parasitic absorption, and programmable interfacial properties without requiring a thick doped hole-transport layer, 16-19 pushing certified efficiencies of small-area single-junction perovskite solar cells beyond 27%. 20-24 Their appeal also derives from a modular molecular architecture, in which an anchoring group binds to the electrode surface, 25-27 a linker defines adsorption geometry and packing, 28,29 and a π-conjugated core governs frontier orbital energies and intermolecular electronic coupling. 30 Since anchoring chemistry is largely dictated by oxide surface functionality, and dipole engineering at the anchor is intrinsically coupled to adsorption robustness and molecular order, recent advances have focused predominantly on the π-core, 31 including asymmetric geometries to improve surface coverage, 21,32 extending π-conjugation to tune the highest occupied molecular orbital (HOMO) and interfacial coupling, functional substituents to suppress interfacial traps or strengthen dipoles, 8,33 and rigidified hydrocarbon frameworks to enhance chemical resilience (Extended Data Fig. 1). 9,34 Despite substantial progress, they typically emphasized either robust bottom-interface binding and energetic regulation at the oxide/SAM contact, or top-interface passivation and crystallization control at the SAM/perovskite contact. 35,36 Such a separation is inherently incomplete, as a SAM-based buried contact constitutes a coupled electrode-SAM-perovskite junction, in which interfacial bonding, molecular orientation and packing, and charge transport across the nanometre-scale organic layer are intrinsically linked. 11-14 Emerging evidence further indicates that charge transfer across practical SAM contacts is often governed by thermally activated hopping through localized states, rather than purely coherent tunneling, 12 rendering charge extraction highly sensitive to molecular geometry and interfacial orbital overlap—parameters not explicitly incorporated into most previous molecular designs. The central challenge, therefore, lies not only in work-function regulating, but in the simultaneous integration of interfacial defect suppression, robust orbital coupling, and low-loss carrier transfer across the molecular contact. Here we establish a geometry-dependent three-layer molecular-contact framework that regards the electrode/SAM interface, the SAM/perovskite interface, and charge transfer across the monolayer as an integrated whole. Using a carbazole-based platform, we incorporate benzothiophene unit into the π-core to construct four regioisomeric architectures and define the geometric origin of interfacial orbital coupling ( Fig. 1a and 1b ). In this design, the phosphonic-acid anchor ensures robust chemisorption to the oxide anode, whereas the sulfur site acts as a soft Lewis base that binds undercoordinated Pb 2+ species at the perovskite surface, 37,38 affording directional dual-side coupling and constrained molecular orientation within a single SAM. Computation and experiment together identify a geometry-dependent principle: when favorable HOMO alignment is preserved, an N-π-S electronic effect strengthens sulfur-mediated coordination, and an L-shaped backbone that exposes sulfur and nitrogen functionalities toward the perovskite maximizes interfacial orbital overlap while minimizing transport loss. Enabled by reduced defect formation and accelerated charge extraction, DBT34ID-based single-junction PSCs achieves a record high power-conversion efficiency (PCE) of 28.11% (certified 27.78% in reverse-scan model and 27.24% in stabilized output), 20-24 and retains >95% of their initial efficiency after 1,500 hours of maximum-power-point tracking (MPPT) according to ISOS-L-2 aging protocol. Geometry-dependent three-layer molecular-contact framework The fused-ring topology and geometric configuration of the π-conjugated scaffold in SAM molecules define the HOMO energy, orbital distribution and intrinsic dipole moment, whereas weak π-π interactions between adjacent units offer only limited control over collective solid-state behavior, particularly intermolecular packing and spatial orientation. 13 Notably, in molecularly thin hole-selective contacts, the orientation of the π-conjugated backbone further governs orbital coupling with both adjacent interfaces and is therefore intrinsically linked to molecular geometry. 10 To correlate molecular geometry with interfacial charge-transfer kinetics, we adopted a dual-anchoring design guided by hard-soft acid-base principles: a phosphonic-acid headgroup chemisorbs to hydroxylated ITO, whereas a sulfur site embedded in the π-conjugated core binds undercoordinated Pb²⁺ at the perovskite surface, establishing bidirectional chemical coupling within a single molecular layer. We select a benzothienocarbazole motif as the π-scaffold because it affords calculated HOMO energies of -5.52 to -5.76 eV, well aligned with typical perovskite valence bands ( E V ), while allowing regioisomeric variation for geometric control ( Fig. 1b ). Single-molecule calculations show HOMOs delocalized across the conjugated framework (Supplementary Fig. S31), consistent with continuous intramolecular hopping pathways. Electrostatic-potential (ESP) maps further localized negative potential at the sulfur site, and an N-π-S electronic effect rendered DBT34ID and DBT32ID the most nucleophilic isomers (ESP minima of about -21.4 kcal mol -1 ), indicating an enhanced propensity for Pb coordination. To translate this design into practical hole-selective contacts, we constructed a three-layer molecular-contact framework in which the electrode-SAM-perovskite junction is treated as an integrated whole. Following the device fabrication sequence, phosphonate chemisorption on hydroxylated ITO was considered first, after which a defect-bearing perovskite fragment was introduced near the SAM π-terminus. Multidimensional energy scans were then used to optimize the binding site, tilt angle, and lateral orientation. The simulations reveal a pronounced geometric dependence of interfacial contact ( Fig. 1c ). The linear isomer DBT32ID preferentially adopts a substrate-parallel configuration with a large π-terminal-oxide separation (d π···A ≈ 7.6 Å). The obtuse-angle L-shaped isomers DBT21ID and DBT43ID reduce this distance to 5.9 and 6.1 Å, respectively, whereas the acute-angle L-shaped isomer DBT34ID projects the conjugated core towards the substrate, shortening d π···A to about 3.3 Å. Such a reduced d π···A distance maximizes frontier-orbital overlap of the π-scaffold across both interfaces and thus favors more efficient interfacial charge-transfer kinetics for PCE optimization. Together, this geometry-dependent three-layer molecular-contact framework defines a transferable design principle for SAMs that integrates oxide binding, perovskite coordination, and transport-efficient interfacial coupling. Interfacial modification and charge extraction dynamics The primary role of a hole-selective SAM is to raise the work function (WF) of the bottom electrode and position its HOMO appropriately with respect to the perovskite E V , thereby enabling efficient hole extraction across the buried contact. 18 Ultraviolet photoelectron spectroscopy (UPS) shows that all four phosphonic-acid SAMs increase the WF of ITO by 1.14 to 1.31 eV relative to bare ITO ( Fig. 2a ), confirming strong interfacial dipole modulation. Among them, DBT21ID yields a Fermi level ( E F = -4.84 eV) closest to that of the perovskite (-4.75 eV), whereas DBT32ID exhibits the largest offset ( E F = -5.11 eV), consistent with its linear conjugated geometry, which favors a more substrate-parallel and laterally displaced adsorption configuration. According the UPS-derived valence-band maxima (VBM), the surface E V values of the SAM-modified ITO substrates were estimated to lie between -5.42 and -5.53 eV ( Fig. 2b ), approaching to the intrinsic perovskite E V of -5.65 eV (Supplementary Fig. S39). The resulting small offsets (Δ E V <0.23 eV) indicate favorable energetic alignment for hole extraction and reduced interfacial voltage loss ( Fig. 2c ). 39 Notably, the E V positions of the adsorbed SAMs deviate from the HOMO trend established by density functional theory and cyclic voltammetry for the isolated molecules (Supplementary Fig. S34). Although DBT32ID possesses the shallowest HOMO, it gives the deepest E V on ITO, whereas DBT34ID, with a substantially deeper isolated-molecule HOMO, exhibits the shallowest E V after adsorption. This contrast discloses that interfacial energetics are governed not only by molecular frontier levels, but also by adsorption-induced WF modulation, orbital hybridization, and packing-induced electronic delocalization. Accordingly, DBT32ID primarily maximizes the WF increase of ITO, whereas DBT34ID promotes stronger π-framework-ITO coupling and tighter packing, leading to greater interfacial delocalization and a higher E V position. To further verify orbital coupling and spatial proximity between ITO and the adsorbed SAMs, we calculate electron-density-difference (EDD) plots for the optimized SAM/ITO interfaces within the geometry-dependent three-layer molecular-contact framework ( Fig. 2d and Supplementary Fig. S33). Although the four isomers share the same sulfur-containing fused heteroaromatic scaffold, their distinct geometries produce markedly different interfacial coupling. DBT34ID, which exhibits the shortest d π ⋯A distance to ITO, reflecting the strongest density redistribution at the SAM/ITO junction, 40-42 consistent with the largest interfacial orbital overlap. By contrast, other benzothienocarbazole (BTCz) isomers, such as DBT21ID, exhibit much weaker coupling due to their larger interfacial separation. Given the comparable effective conjugation areas of the four isomers, and charge transport in amorphous organic aggregates is generally dominated by intermolecular hopping, the combined UPS and EDD results identify interfacial geometry as the dominant factor governing vertical charge transfer, with DBT34ID providing the most favorable configuration. Conductive atomic force microscopy (C-AFM) further supports this interpretation. All SAMs uniformly cover ITO and form continuous conductive pathways, indicating homogeneous monolayer formation, yet DBT34ID delivers nearly an order-of-magnitude higher current than DBT21ID ( Fig. 2e and Extended Data Fig. 2a), evidencing substantially lower vertical transport resistance. 1,5,43 We next examined charge-transfer dynamics after perovskite deposition by femtosecond transient absorption (fs-TA) spectroscopy. Because optical absorption is dominated by the thick perovskite layer, the signal primarily reflects bulk-dominated carrier dynamics on the sub-nanosecond timescale. The fitted average decay lifetime ( τ avg ) follows the order DBT34ID > DBT21ID (Fig. 2f and 2g ), consistent with progressively improved interfacial passivation, reduced defect-assisted recombination, and suppressed non-radiative decay. 11 Time-resolved photoluminescence (TRPL) measurements provides an independent assessment. On insulating quartz, where interfacial extraction is negligible, all SAM-treated films show longer photoluminescence lifetimes than the SAM-free control (Supplementary, Fig. S36), and DBT34ID produces the largest increase ( Fig. 2h ), indicating the most effective defect suppression. On ITO, by contrast, where hole extraction is operative, the lifetimes become strongly SAM-dependent and decrease most markedly for DBT34ID ( Fig. 2i ), corroborating the fastest interfacial charge extraction. 40 Together, these results suggest that DBT34ID provide the most favorable combination of energetic alignment, interfacial orbital coupling, defect suppression, and carrier-transfer kinetics. Interfacial chemical passivation and perovskite morphology X-ray photoelectron spectroscopy (XPS) identifies the chemical origin of the different passivation strengths. Relative to pristine perovskite, DBT34ID shifts the Pb 4f envelope to lower binding energy by ~0.21 eV and narrows its linewidth, consistent with Pb-S coordination and a reduced density of undercoordinated Pb-related defect states at the buried interface, 37 whereas DBT21ID induces only marginal changes ( Fig. 3a ). Complementary evidence is provided by the S 2p spectra: after contact with perovskite, DBT34ID shows a clear shift to higher binding energy (~0.17 eV), further supporting sulfur involvement in interfacial Pb binding, 37 whereas DBT21ID shows negligible perturbation ( Fig. 3b ). Fourier-transform infrared spectroscopy further supports this assignment, 38 with DBT34ID showing a more pronounced change in the relative intensity of the C-S stretching vibration, together with slight band broadening, after perovskite deposition. (Supplementary Fig. S38). Together, these results indicate stronger sulfur-mediated coordination to Pb-related defect sites for DBT34ID. This stronger dual-side coupling also influences perovskite crystallization. Surface Scanning electron microscope (SEM) reveals a clear morphological contrast among the SAMs ( Fig. 3c and Extended Data Fig. 2b). Perovskite film grown on DBT21ID exhibits frequent pinholes and nanovoids, indicative of incomplete grain coalescence and a higher density of buried interfacial defects. 44,45 In contrast, DBT34ID yields a compact, uniformly fused grain network with essentially void-free coverage. Cross-sectional SEM further shows that DBT34ID produces a flatter and more continuous buried interface, a denser and more uniform perovskite layer, and fewer interfacial voids than DBT21ID, affording improved contact quality and structural integrity. 17,46,47 Atomic force microscopy demonstrates similar surface roughness for all SAM-treated films (Rq ≈ 28 to 31 nm), reflecting that these differences arose primarily from defect morphology rather than global topographic roughness (Supplementary Fig. S41 and S42). 48 In addition to the morphology, different SAMs also greatly affects the crystallinity of perovskite films, which is corroborated with these structural differences ( Fig. 3d ). From Grazing-incidence wide-angle x-ray scattering (GIWAXS), perovskite on DBT21ID shows broad, weak Debye–Scherrer rings with a pronounced diffuse background, consistent with greater microstructural disorder and smaller coherent scattering domains. By contrast, DBT34ID produces sharper and more intense Bragg features, a higher peak-to-background ratio, and clearly higher- q reflections, indicating improved crystallinity and reduced defect-associated diffuse scattering. 44,48 Its more anisotropic azimuthal intensity distribution also suggests a higher degree of preferred orientation. However, conventional GIWAXS and X-Ray Diffraction reveal only marginal differences among the films, indicating that DBT34ID enhances crystallographic order, orientational distribution, and local packing quality without fundamentally altering the crystalline phase (Extended Data Fig. 3). 49 These structural differences are further reflected in the optical response. PL mapping revealed that DBT34ID yielded stronger and more spatially uniform emission, with fewer low-intensity domains, consistent with reduced trap-assisted nonradiative recombination and improved film homogeneity ( Fig. 3e ). 38 Steady-state PL measurements showed the same trend, with DBT34ID delivering a much stronger PL enhancement than DBT21ID, consistent with more effective suppression of Shockley–Read–Hall recombination. (Extended Data Fig. 4). 50 Photovoltaics performance and stability Consistent with its more favorable orbital coupling, stronger sulfur-mediated passivation, and reduced transport loss at the buried contact, DBT34ID delivered the best performance in devices with the architecture ITO/DBT-derivative SAMs/perovskite/1,3-diaminopropane dihydroiodide (PDADI)/ fullerene (C 60 )/ bathocuproine (BCP)/Ag ( Fig. 4a ). The champion 0.050-cm² device achieved a PCE of 28.11% (27.78% certified by the National PV Industry Measurement and Testing Center; Fig. 4b ) with negligible hysteresis, enabled by concurrent improvements in open-circuit voltage ( V OC , 1.21 V), short-circuit current density ( J SC , 26.75 mA cm - ²), and fill factor (FF, 86.69%), thereby establishing a new benchmark for single-junction PSCs. 20,23 The steady output of the champion device also reaches 27.84% (27.24% certified by the National PV Industry Measurement and Testing Center; Supplementary Fig. S43), representing the highest reported steady-state PCE. 21 To maximize photocurrent, we introduced an evaporated MgF 2 antireflection coating for optical management, and the resulting enhancement in light harvesting was confirmed by external quantum efficiency measurements, which yielded an integrated J SC of 25.66 mA cm -2 ( Fig. 4c ). By comparison, the other regioisomers delivered lower champion PCEs of 26.52% for DBT21ID, 27.17% for DBT32ID, and 27.28% for DBT43ID. DBT34ID-based devices also exhibited the narrowest PCE distribution ( Fig. 4d ), indicating that the optimized molecular geometry improves not only peak efficiency but also device reproducibility. The performance advantage of DBT34ID is maintained across device formats relevant to practical deployment. In 1-cm 2 devices, DBT34ID achieved a champion PCE of 25.28%, with a V OC of 1.163 V, a J SC of 25.55 mA cm − 2 , and an FF of 85.06%, outperforming DBT21ID (24.76%), DBT32ID (24.59%), and DBT43ID (25.06%) ( Fig. 4e and Extended Data Table 1). To evaluate its applicability to tandem photovoltaics, we further examined wide-bandgap devices based on a 1.68 eV perovskite absorber. DBT34ID based device again gives the best result, delivering a champion PCE of 24.99%, with a V OC of 1.257 V, a J SC of 23.37 mA cm −2 , and an FF of 85.02%, compared with 24.02% for DBT21ID, 23.38% for DBT32ID, and 24.44% for DBT43ID ( Fig. 4f ). The retention of this performance hierarchy across active area and bandgap indicates that the benefit of DBT34ID is not device-specific, but originates from a more general improvement in buried-contact quality. We next evaluate device stability under multiple aging protocols. Under damp-heat aging at 85°C and 85% relative humidity with encapsulation (ISOS-D-3, 10 devices), DBT34ID-based devices retained about 95.1% of their initial efficiency after ~1,000 hours, compared with 84.8% for DBT21ID, 91.0% for DBT32ID, and 92.6% for DBT43ID ( Fig. 4 g ). Under continuous maximum-power-point tracking at 65°C under 100 mW cm − 2 illumination in N 2 (ISOS-L-2), DBT34ID-based devices retained about 95.2% of their initial efficiency after ~1,500 hours, whereas DBT21ID-, DBT32ID-, and DBT43ID-based devices decreased to about 82.8%, 88.7%, and 91.0%, respectively ( Fig. 4h ). We attribute this enhanced operational stability to the optimized interfacial configuration of DBT34ID, which preserves a kinetically efficient and chemically resilient buried contact under prolonged bias, illumination, and thermal stress. Discussion Our results identify the buried contact in inverted PSCs as an integrated electrode-SAM-perovskite junction and define a geometry-dependent three-layer molecular-contact framework that links molecular binding geometry to interfacial energetics, defect passivation and charge-transfer kinetics. Within the BTCz platform, regioisomeric control reveals a clear geometry-function relationship: reinforced by an N-π-S electronic motif, the embedded sulfur site strengthens coordination to defective Pb²⁺, whereas the acute-angled L-shaped geometry projects the sulfur and nitrogen functionalities towards the perovskite while preserving efficient orbital overlap across the buried junction. This geometry-dependent coupling simultaneously strengthens defect passivation and vertical charge transfer, leading to improved interfacial order, reduced non-radiative recombination, faster charge extraction, and concurrent gains in efficiency and operational stability. More broadly, these findings establish a transferable design principle for SAM-based buried contacts: high performance arises from the integration of chemical functionality with molecular geometries that enable efficient interfacial coupling and charge transfer. Transport-aware dual-side coupling thus provides a molecular design route to higher-performance inverted PSCs and scalable single-junction and tandem perovskite photovoltaics. Declarations Author Contributions X.Y. conceived the original idea. X.C., J.X. and M.Y. carried out the molecular synthesis, structural characterization and optimization of the experimental protocols under the supervision of X.Y. and C.Y. Perovskite films and devices were fabricated by S.Y., B.X. Y.S., X.L., Z.W., Z.S. and B.Z. under the supervision of H.Y. and Z.O. Data analysis and discussion were performed by C.Z., T.Z. and X.Y. Theoretical calculations were performed by C.Z. and X.Y. under the supervision of C.Y. X.Y. wrote the manuscript, with revisions from T.Z. and C.Y. All authors discussed the results and commented on the manuscript. C.Y. supervised the project. Data availability All data supporting the findings of this study are available within the Article and its Supplementary Information. Source data are available from the corresponding authors upon reasonable request. Competing interests The authors declare no competing interests. Acknowledgements This research was financially supported by the National Natural Science Foundation of China (Nos. 22575155 and 52503337), Guangdong Basic and Applied Basic Research Foundation (Nos. 2024A1515010744), the Shenzhen Science and Technology Program (ZDSYS20210623091813040) and the Research Team Cultivation Program of Shenzhen University (2023DFT004). Open Research Fund of State Key Laboratory of Photovoltaic Science and Technology (No. PVST252208). The authors also thank the Instrumental Analysis Center of Shenzhen University for analytical support. References Li, Q. et al. Graphene-polymer reinforcement of perovskite lattices for durable solar cells. Science 387 , 1069-1077 (2025). Liu, S. et al. Buried interface molecular hybrid for inverted perovskite solar cells. Nature 632 , 536-542 (2024). Liang, Y. et al. A matrix-confined molecular layer for perovskite photovoltaic modules. Nature 648 , 91-96 (2025). Jiang, W. et al. Toughened self-assembled monolayers for durable perovskite solar cells. Nature 646 , 95-101 (2025). Jia, L. et al. Efficient perovskite/silicon tandem with asymmetric self-assembly molecule. Nature 644 , 912-919 (2025). Li, G. et al. Stabilizing high-efficiency perovskite solar cells via strategic interfacial contact engineering. Nat. Photonics 20 , 55-62 (2025). Wu, W. et al. Stable and uniform self-assembled organic diradical molecules for perovskite photovoltaics. Science 389 , 195-199 (2025). Li, Z. et al. Stabilized hole-selective layer for high-performance inverted p-i-n perovskite solar cells. Science 382 , 284-289 (2023). Zhao, K. et al. peri-Fused polyaromatic molecular contacts for perovskite solar cells. Nature 632 , 301-306 (2024). Li, T. et al. Tin-based perovskite solar cells with a homogeneous buried interface. Nature 648 , 84-90 (2025). Yang, W. et al. Axially chiral molecular contacts with low isomerization barriers for perovskite solar cells. Nat. Photonics , DOI: 10.1038/s41566-41025-01817-41568 (2026). Fang, F. et al. Electron hopping in conjugated molecular wires with application to solar cells. Nat. Chem. 18 , 756–764 (2026). Li, T. et al. Quasi-random oriented molecular contacts for inverted perovskite solar cells with improved efficiency. Nat. Energy , DOI: 10.1038/s41560-41026-02024-41567 (2026). Peng, C. et al. Strengthened Perovskite/SAM Heterointerface for Stable Perovskite Solar Cells. J. Am. Chem. Soc. 147 , 48391-48399 (2025). Han, P. & Zhang, Y. Recent Advances in Carbazole‐Based Self‐Assembled Monolayer for Solution‐Processed Optoelectronic Devices. Adv. Mater. 36 , 2405630 (2024). Zhang, S. et al. Minimizing buried interfacial defects for efficient inverted perovskite solar cells. Science 380 , 404-409 (2023). Tan, Q. et al. Inverted perovskite solar cells using dimethylacridine-based dopants. Nature 620 , 545-551 (2023). Shin, S. S. et al. Interlayer engineering in metal halide perovskite photovoltaics. Nat. Photonics 20 , 11-23 (2026). Morales, C. A. F. et al. Multilayer Formation, Interfacial Binding, and Stability of Self-Assembled Molecules in Perovskite Solar Cells. J. Am. Chem. Soc. 147 , 48136-48146 (2025). Xiong, Z. et al. Homogenized chlorine distribution for >27% power conversion efficiency in perovskite solar cells. Science 390 , 638-642 (2025). Tian, C. et al. Photostable donor–acceptor interface for minimizing energy loss in inverted perovskite solar cells. Nat. Photonics , DOI: 10.1038/s41566-41025-01827-41566 (2026). Zhang, Z. et al. Photoswitchable isomers to improve grain boundary resilience and perovskite solar cells stability under light cycling. Nat. Energy , DOI: 10.1038/s41560-41026-01993-z (2026). Yang, Y. et al. Molecular Buffering Regulates Lattice Strain for Fatigue‐Resistant Perovskite Photovoltaics Under Cryogenic Thermal Cycling. Adv. Mater. 38 , e19339 (2026). Lu, H. et al. Ion‐Defect Dual Management for Achieving Efficient Air‐Processed Perovskite Solar Cells With Certified Efficiency 27.1%. Adv. Mater. 38 , e17596 (2026). Fei, C. et al. Limiting phosphonic acid interlayer–perovskite reactivity to stabilize perovskite solar modules. Science 391 , eadz7969 (2026). Luo, C. et al. Engineering bonding sites enables uniform and robust self-assembled monolayer for stable perovskite solar cells. Nat. Mater. 24 , 1265-1272 (2025). Wang, J. et al. Less-acidic boric acid-functionalized self-assembled monolayer for mitigating NiOx corrosion for efficient all-perovskite tandem solar cells. Nat. Commun. 16 , 4148 (2025). Yang, J. et al. Flexibility meets rigidity: a self-assembled monolayer materials strategy for perovskite solar cells. Nat. Commun. 16 , 6968 (2025). Wang, D. et al. Rigid molecules anchoring on NiOx enable >26% efficiency perovskite solar cells. Joule 9 , 101815 (2025). Qu, G. et al. Self-assembled materials with an ordered hydrophilic bilayer for high performance inverted Perovskite solar cells. Nat. Commun. 16 , 86 (2025). Yuan, L. et al. Perovskite Solar Cells and Light Emitting Diodes: Materials Chemistry, Device Physics and Relationship. Chem. Rev. 125 , 5057-5162 (2025). Wang, J. et al. Asymmetric Self‐Assembled Molecule With High Dipole Moment for Efficient Wide‐Bandgap Perovskite Solar Cells and Tandems. Adv. Mater. 38 , e23338 (2026). Zhu, H. et al. Improved Hole‐Selective Contact Enables Highly Efficient and Stable FAPbBr3 Perovskite Solar Cells and Semitransparent Modules. Adv. Mater. 36 , 2406872 (2024). Luo, Y. et al. Bulk nano-heterointerface secures molecular contacts in perovskite solar cells. Nat. Mater. , DOI: 10.1038/s41563-41026-02546-41561 (2026). Wang, D. et al. Self-assembled molecules with hydrogen-bond networks enable efficient all-perovskite tandem solar cells. Nat. Energy 11 , 436-448 (2026). Gao, D. et al. Autonomous closed-loop framework for reproducible perovskite solar cells. Nature (2026). Yao, S. et al. Sulfur‐Modulated Fully‐Conjugated Self‐Assembled Monolayers for Synergistic Dual‐Interface Optimization in Inverted Perovskite Solar Cells. Angew. Chem. Int. Ed. , DOI: 10.1002/anie.5319815 (2026). Shao, G. et al. Reducing Interface Energy Loss of Perovskite Solar Cells by Molecular Engineering of Hole‐Transporting Materials. Angew. Chem. Int. Ed. 65 , e23799 (2026). Park, S. M. et al. Low-loss contacts on textured substrates for inverted perovskite solar cells. Nature 624 , 289-294 (2023). Chen, H. et al. Improved charge extraction in inverted perovskite solar cells with dual-site-binding ligands. Science 384 , 189-193 (2024). Li, M. et al. A molecularly engineered electron-selective self-assembled monolayer enhances quasi-Fermi level splitting in inverted perovskite solar cells. Nat. Energy , DOI: 10.1038/s41560-41026-02025-41566 (2026). Dong, B. et al. Self-assembled bilayer for perovskite solar cells with improved tolerance against thermal stresses. Nat. Energy 10 , 342-353 (2025). Feng, K. et al. Non-fullerene electron-transporting materials for high-performance and stable perovskite solar cells. Nat. Mater. 24 , 770-777 (2025). Hu, J. et al. Molecular press annealing enables robust perovskite solar cells. Science 391 , 164-170 (2026). Peng, J. et al. Maximizing perovskite electroluminescence with ordered 3D/2D heterojunction. Nature 651 , 76-82 (2026). Wang, Y. et al. Improved solvent systems for commercially viable perovskite photovoltaic modules. Science 390 , 1021-1028 (2025). Li, X. et al. Multimodal electron microscopy of halide perovskite interfacial dynamics. Nature 651 , 614-620 (2026). Chang, X. et al. Multivalent ligands regulate dimensional engineering for inverted perovskite solar modules. Science 391 , 153-159 (2026). Li, S. et al. High-efficiency and thermally stable FACsPbI3 perovskite photovoltaics. Nature 635 , 82-88 (2024). Liu, S. et al. Solvated-intermediate-driven surface transformation of lead halide perovskites. Nat. Energy 11 , 109–120 (2026). Methods Materials: Unless otherwise noted, all reagents and solvents were used as received without further purification. Anhydrous N,N -dimethylformamide (DMF, 99.8%), dimethyl sulfoxide (DMSO, 99.9%), ethanol (EtOH, 99.5%) and chlorobenzene (CB, 99.8%) were purchased from Advanced Election Technology Co., Ltd., whereas isopropanol (IPA, 99.5%) was purchased from Aladdin. Lead iodide (PbI 2 ) was purchased from TCI. Other perovskite precursor materials, including formamidinium iodide (FAI), cesium iodide (CsI), methylammonium iodide (MAI) and methylammonium chloride (MACl), together with C 60 and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), were purchased from Xi’an Yuri Solar Co., Ltd., China. Key synthetic intermediates, including 5 H -benzo[4,5]thieno[3,2- c ]carbazole, 11 H -benzo[4,5]thieno[3,2- b ]carbazole, dibenzo[ b , d ]thiophen-1-ylboronic acid, 1-bromo-2-nitrobenzene and 12 H -benzo[4,5]thieno[3,2- a ]carbazole, were obtained from Shanghai Bidepharm Technology Co., Ltd. or Shanghai Haohong Biomedical Technology Co., Ltd. Theoretical calculations: Single-molecule calculations were performed using Gaussian 16. Ground-state geometries and electronic structures were obtained at the B3LYP/6-311++G(d,p) level with Grimme’s D3 dispersion correction and Becke-Johnson damping. Harmonic frequency calculations confirmed that all optimized structures were true minima on the potential-energy surface, with no imaginary frequencies. All calculations were carried out in the gas phase. Molecular structures and orbitals were visualized using GaussView 6.0 and VMD 1.9.3, 51,52 and wavefunction analyses were performed with Multiwfn 3.8. 53 The geometry-dependent three-layer molecular-contact framework was constructed stepwise. An oxide substrate was first generated from the In 2 O 3 (111) surface using a three-layer slab, after which the terminal phosphonic-acid group of each SAM was deprotonated to represent chemisorption on the oxide surface. A perovskite slab was then placed above the SAM layer to model interfacial defect passivation at the buried contact. Interfacial configuration sampling was accelerated using the MACE-MPA-0 machine-learning potential, and the lowest-energy structure was used for first-principles optimization. First-principles calculations were performed using CP2K within the PBE generalized-gradient approximation with DFT-D3(BJ) dispersion correction, using the GPW scheme with the DZVP-MOLOPT-SR-GTH basis set and corresponding GTH pseudopotentials. The bottom ITO layer and the topmost perovskite atomic layer were fixed during structural relaxation to mimic substrate and bulk constraints. Perovskite film and device fabrication: PSCs were fabricated with the architecture ITO/SAMs/Cs 0.005 FA 0.995 PbI 3 /C 60 /BCP/Ag. Cleaned ITO glass substrates were treated with UV-ozone for 15 min. Different SAM solutions in IPA (1 mg mL -1 ) were then spin-coated onto the substrates at 3,000 rpm for 30 s, followed by annealing at 100 °C for 10 min. The perovskite layer was deposited by a one-step spin-coating process. CsI (2.49 mg), PbI 2 (933.42 mg), FAI (322.85 mg) and MACl (31.73 mg) were dissolved in 1 mL of mixed solvent containing DMSO (200 μL) and DMF (800 μL), and the solution was stirred at 25 °C for 8 h. After filtration, the precursor solution was spin-coated onto the SAM-modified substrates at 6,000 rpm for 60 s, during which 220 μL of chlorobenzene was dropped onto the spinning substrate in the final 15 s. The films were then annealed at 110 °C for 20 min. Subsequently, a PDADI solution in IPA (1 mg mL -1 ) was spin-coated onto the perovskite films at 3,000 rpm for 30 s, followed by annealing at 100 °C for 10 min. The samples were then transferred to a thermal evaporator for sequential deposition of C 60 (25 nm), BCP (5 nm) and Ag (100 nm). Finally, an MgF 2 anti-reflection layer with a thickness of approximately 120 nm was deposited on the glass side by thermal evaporation. Solar cell characterization: Current density-voltage (𝐽-𝑉) characteristics were measured at room temperature in a nitrogen-filled glovebox using a Keithley 2410 source meter under simulated AM 1.5G illumination from a xenon arc lamp. The light intensity was calibrated before measurement using a Sciencetech SCI-REF-Q silicon reference cell. No preconditioning was applied, and the scan time was 10 s. The active area of the devices was defined by an opaque metal mask with an aperture area of 0.058 cm 2 or 1.004 cm 2 . External quantum efficiency (EQE) measurements were performed without applied bias in ambient air using an MNPVQE300 Quantum Efficiency Measurement System (Millennial Solar). Bias illumination was provided by bright LEDs with emission peaks at 900 nm and 400 nm. Stability tests of solar cells: For thermal and humidity stability measurements, devices were stored under damp-heat conditions at 85 °C and 85% relative humidity, and J -V curves were recorded periodically. For long-term maximum power point tracking (MPPT), devices were measured under an LED-based solar simulator calibrated to approximately 1 sun with a standard silicon reference cell. Samples were placed in a tightly sealed chamber under continuous N 2 flow. During operation, the device temperature was maintained at approximately 65 °C and monitored by an internal sensor. The steady-state power output was tracked at a constant bias of 1000 mV using a system supplied by Wuhan 91PVK Solar Technology, while J -V curves were recorded periodically throughout the test. Other characterizations: UV-vis absorption spectra were recorded on a Shimadzu UV-2700 spectrophotometer using solutions ( 1 × 10 -5 M ) at room temperature. PL spectra were measured on a Hitachi F-7100 fluorescence spectrophotometer at 298 K . PL mapping was performed on a PicoQuant MicroTime 100/FluoTime 100 system using a 405 nm pulsed diode laser ( PDL 828 ‘Sepia II’ ). TRPL decay curves were collected on a FluoTime 300 system (PicoQuant GmbH) with a 375 nm picosecond pulsed diode laser. fs-TA spectroscopy was performed using a frequency-doubled mode-locked Ti:sapphire femtosecond laser (Coherent) coupled to an optical parametric amplifier . The 35 fs, 1 kHz output was split to generate 600 nm pump pulses and a white-light continuum probe (320-650 nm) ; the pump fluence was 1 μJ cm -2 per pulse. Absolute PL quantum yields of perovskite films were measured on a Hamamatsu C13534 UV-NIR spectrometer equipped with an integrating sphere under dry Ar, using 320 nm excitation. FTIR spectra were recorded on a Nicolet 6700 spectrometer. CV measurements were carried out on a CHI600 electrochemical workstation at 100 mV s -1 using a three-electrode configuration with a glassy carbon working electrode, a Pt wire counter electrode and an Ag/AgCl reference electrode. UPS and XPS measurements were performed on a Thermo Scientific ESCALAB 250Xi system using He I radiation (21.22 eV) and monochromated Al K α radiation (1486.6 eV) , respectively. GIWAXS measurements were performed at the BL14B1 beamline of the Shanghai Synchrotron Radiation Facility using an X-ray wavelength of 0.12398 nm . AFM measurements were conducted on a Dimension FastScan system (Bruker). KPFM images were acquired on an Asylum Cypher S microscope (Oxford Instruments) using a Ti–Ir-coated ASYELEC.01-R2 cantilever ( k = 4 ± 0.5 N m -1 ). SEM images were obtained on a Zeiss Sigma 300 field-emission microscope equipped with an Oxford Xplore 30 energy-dispersive X-ray spectrometer, operating in secondary-electron mode at 3 kV after Au sputter-coating. 51. M. J. Frisch, G. W. T., H. B. Schlegel, G. E. Scuseria, et al. Gaussian 16, Revision A.03 (Gaussian, Inc.: Wallingford CT, 2016). 52. Liu, Z. et al. An sp-hybridized all-carboatomic ring, cyclo[18]carbon: Electronic structure, electronic spectrum, and optical nonlinearity. Carbon 165 , 461-467 (2020). 53. Lu, T. & Chen, F. Multiwfn: A multifunctional wavefunction analyzer. J. Comput. Chem. 33 , 580-592 (2012). Additional Declarations There is NO Competing Interest. Supplementary Files SupplementaryInformation.docx Supplementary Information ExtendedData.docx Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9432790","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Physical Sciences - Article","associatedPublications":[],"authors":[{"id":634986062,"identity":"56ff15d8-5068-4fb6-8f93-0c126a761acf","order_by":0,"name":"Chuluo Yang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzElEQVRIiWNgGAWjYDACdjBpA+HwEKWFGUymka7lMAla+Jt5DD8X/DpvLz8jgfHB2zYGeXNCWiQO8xhLz+y7ndg4I4HZcG4bg+HOBgJaDJh5DKR5e24nMEsksEnztjEkGBwgrMX4N2/POXs2iQT238RqMZPm+XGAsQdoCzNRWiQOs5VZ8zYkJ87gedgsOeechOEGQlr425s33+b5Y2cv35588MObMht5grYwMHAYMDC2gRiMDSBbCaoHAvYHDAx/iFE4CkbBKBgFIxYAAEAaNvGceZweAAAAAElFTkSuQmCC","orcid":"","institution":"Shenzhen University","correspondingAuthor":true,"prefix":"","firstName":"Chuluo","middleName":"","lastName":"Yang","suffix":""},{"id":634986063,"identity":"9c78edf7-1572-42ef-956e-57f0bc0b0aca","order_by":1,"name":"Suhao Yan","email":"","orcid":"","institution":"Research and Development Center, JA Solar","correspondingAuthor":false,"prefix":"","firstName":"Suhao","middleName":"","lastName":"Yan","suffix":""},{"id":634986064,"identity":"1d040223-4ad6-4937-9a82-6c4ce1735b2c","order_by":2,"name":"Xiaojun Yin","email":"","orcid":"","institution":"Shenzhen University","correspondingAuthor":false,"prefix":"","firstName":"Xiaojun","middleName":"","lastName":"Yin","suffix":""},{"id":634986065,"identity":"f95c5ab8-7fd2-4c5a-9355-2b986721876b","order_by":3,"name":"Bo Xiao","email":"","orcid":"","institution":"Research and Development Center, JA Solar","correspondingAuthor":false,"prefix":"","firstName":"Bo","middleName":"","lastName":"Xiao","suffix":""},{"id":634986066,"identity":"f1ea03d4-0337-49e0-b4e8-c636f22f6833","order_by":4,"name":"Xuefeng Chen","email":"","orcid":"","institution":"Shenzhen University","correspondingAuthor":false,"prefix":"","firstName":"Xuefeng","middleName":"","lastName":"Chen","suffix":""},{"id":634986067,"identity":"5bd4d8ae-76b8-4cf0-b394-cb83f9a269be","order_by":5,"name":"Jisheng Xu","email":"","orcid":"","institution":"Shenzhen University","correspondingAuthor":false,"prefix":"","firstName":"Jisheng","middleName":"","lastName":"Xu","suffix":""},{"id":634986068,"identity":"9a195e6f-68f4-4c7e-805d-09c654839953","order_by":6,"name":"Ming Yang","email":"","orcid":"","institution":"Shenzhen University","correspondingAuthor":false,"prefix":"","firstName":"Ming","middleName":"","lastName":"Yang","suffix":""},{"id":634986069,"identity":"8145a023-2f6a-4493-92f3-526a6a693b7c","order_by":7,"name":"Tiankai Zhang","email":"","orcid":"https://orcid.org/0009-0002-6019-9018","institution":"Southeast University","correspondingAuthor":false,"prefix":"","firstName":"Tiankai","middleName":"","lastName":"Zhang","suffix":""},{"id":634986070,"identity":"77604f02-30c1-444d-b468-1118d8c072cf","order_by":8,"name":"Cheng Zhong","email":"","orcid":"","institution":"Wuhan University","correspondingAuthor":false,"prefix":"","firstName":"Cheng","middleName":"","lastName":"Zhong","suffix":""},{"id":634986071,"identity":"1d6c660f-af58-488b-ac28-435e209d9361","order_by":9,"name":"Yang Sun","email":"","orcid":"","institution":"Research and Development Center, JA Solar","correspondingAuthor":false,"prefix":"","firstName":"Yang","middleName":"","lastName":"Sun","suffix":""},{"id":634986072,"identity":"af9698c8-c4c5-4784-8e85-ca3295636f3e","order_by":10,"name":"Bo Zhang","email":"","orcid":"","institution":"JA Solar","correspondingAuthor":false,"prefix":"","firstName":"Bo","middleName":"","lastName":"Zhang","suffix":""},{"id":634986073,"identity":"be12bfcc-ca46-4ccc-9475-a8c781a064b5","order_by":11,"name":"Xiyang Li","email":"","orcid":"","institution":"Southeast University","correspondingAuthor":false,"prefix":"","firstName":"Xiyang","middleName":"","lastName":"Li","suffix":""},{"id":634986074,"identity":"4018b35e-1e58-4aa8-90ac-aaf987f604ab","order_by":12,"name":"Zhenxu Wang","email":"","orcid":"","institution":"Southeast University","correspondingAuthor":false,"prefix":"","firstName":"Zhenxu","middleName":"","lastName":"Wang","suffix":""},{"id":634986075,"identity":"1e2f6f6b-2001-4bc5-9649-f5d54050c255","order_by":13,"name":"Zhengming Sun","email":"","orcid":"https://orcid.org/0000-0001-9798-9385","institution":"Southeast University","correspondingAuthor":false,"prefix":"","firstName":"Zhengming","middleName":"","lastName":"Sun","suffix":""},{"id":634986076,"identity":"dd7f05d4-25b5-48c3-a3d0-bf7d88be5e4c","order_by":14,"name":"Haipeng Yin","email":"","orcid":"","institution":"Research and Development Center, JA Solar","correspondingAuthor":false,"prefix":"","firstName":"Haipeng","middleName":"","lastName":"Yin","suffix":""},{"id":634986077,"identity":"0ce24983-094a-4960-8737-a7be6932b9f3","order_by":15,"name":"Zi Ouyang","email":"","orcid":"","institution":"Research and Development Center, JA Solar","correspondingAuthor":false,"prefix":"","firstName":"Zi","middleName":"","lastName":"Ouyang","suffix":""}],"badges":[],"createdAt":"2026-04-16 04:00:51","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9432790/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9432790/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108675404,"identity":"b567a47b-0c6c-4f2f-aeba-13d95a7a4f78","added_by":"auto","created_at":"2026-05-07 08:26:03","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":391231,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThree-layer molecular-contact model for geometry-dependent SAM design.\u003c/strong\u003e \u003cstrong\u003ea) \u003c/strong\u003eSchematic of the three-layer molecular-contact model, illustrating the coupled optimization of the electrode/SAM interface, the SAM/perovskite interface, and geometry-dependent charge transfer across the monolayer. \u003cstrong\u003eb) \u003c/strong\u003eChemical structures of four regioisomeric benzothienocarbazole SAMs with calculated HOMOs, electrostatic-potential maps, and local charge-density extrema at the sulfur site. \u003cstrong\u003ec)\u003c/strong\u003e Optimized interfacial geometries showing the minimum π-framework-to-ITO distance (\u003cem\u003ed\u003c/em\u003e\u003csub\u003eπ···A\u003c/sub\u003e).\u003c/p\u003e","description":"","filename":"Picture1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9432790/v1/284ef90312530e73ae21f899.jpg"},{"id":108675429,"identity":"51c5fb4c-b2e0-46ce-bdcd-2e24b385ef9c","added_by":"auto","created_at":"2026-05-07 08:26:05","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":361925,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eEnergetics and charge-transfer dynamics of SAM-modified buried interfaces.\u003c/strong\u003e UPS spectra of SAM-modified ITO in the \u003cstrong\u003ea)\u003c/strong\u003esecondary-electron cutoff and \u003cstrong\u003eb)\u003c/strong\u003e Fermi-edge regions. \u003cstrong\u003ec)\u003c/strong\u003eEnergy-level alignment derived from the UPS results. \u003cstrong\u003ed)\u003c/strong\u003eElectron-density-difference plots for optimized ITO/SAM interfaces within the geometry-dependent three-layer molecular-contact framework. \u003cstrong\u003ee)\u003c/strong\u003e C-AFM images of SAM-modified ITO substrates. The fs-TA spectra of perovskite films deposited on \u003cstrong\u003ef)\u003c/strong\u003eDBT21ID and \u003cstrong\u003eg)\u003c/strong\u003e DBT34ID. TRPL decay curves of \u003cstrong\u003eh)\u003c/strong\u003equartz/SAM/perovskite and \u003cstrong\u003ei) \u003c/strong\u003eITO/SAM/perovskite samples.\u003c/p\u003e","description":"","filename":"Picture2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9432790/v1/7ac8ad22b2850f24297f5768.jpg"},{"id":108675463,"identity":"cf8ac618-8517-4afa-a8c1-2d46bd070428","added_by":"auto","created_at":"2026-05-07 08:26:09","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":323659,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSulfur-mediated interfacial passivation improves buried-interface quality and perovskite structural order.\u003c/strong\u003e \u003cstrong\u003ea)\u003c/strong\u003ePb 4f XPS spectra of different SAMs deposited on ITO/perovskite substrates. \u003cstrong\u003eb)\u003c/strong\u003eS 2p XPS spectra of the SAMs deposited on bare ITO or ITO/perovskite substrates. \u003cstrong\u003ec)\u003c/strong\u003e Top-view and cross-sectional SEM images of ITO/SAM/perovskite films formed on DBT21ID- and DBT34ID-modified substrates. \u003cstrong\u003ed)\u003c/strong\u003eGIWAXS patterns of the corresponding perovskite films. \u003cstrong\u003ee)\u003c/strong\u003ePhotoluminescence (PL) maps of perovskite films deposited on DBT21ID- and DBT34ID-modified ITO substrates.\u003c/p\u003e","description":"","filename":"Picture3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9432790/v1/938363b7a977b8d564be9cb1.jpg"},{"id":108675466,"identity":"6875da50-ead3-4eb8-b44e-86bc15625c0a","added_by":"auto","created_at":"2026-05-07 08:26:10","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":334808,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003ePhotovoltaic performance, application versatility, and stability enabled by SAM engineering.\u003c/strong\u003e \u003cstrong\u003ea)\u003c/strong\u003e Schematic of the device architecture. \u003cstrong\u003eb)\u003c/strong\u003e Reverse-scan \u003cem\u003eJ\u003c/em\u003e–\u003cem\u003eV\u003c/em\u003e curves of champion small-area devices (0.058 cm\u003csup\u003e2\u003c/sup\u003e) based on different SAMs. \u003cstrong\u003ec)\u003c/strong\u003e EQE spectra and integrated \u003cem\u003eJ\u003c/em\u003e\u003csub\u003eSC\u003c/sub\u003e values. \u003cstrong\u003ed)\u003c/strong\u003e Statistical distributions of \u003cem\u003eV\u003c/em\u003e\u003csub\u003eOC\u003c/sub\u003e, \u003cem\u003eJ\u003c/em\u003e\u003csub\u003eSC\u003c/sub\u003e, FF, and PCE. \u003cstrong\u003ee)\u003c/strong\u003e Reverse-scan \u003cem\u003eJ\u003c/em\u003e–\u003cem\u003eV\u003c/em\u003e curves of champion large-area devices (1.004 cm\u003csup\u003e2\u003c/sup\u003e). \u003cstrong\u003ef)\u003c/strong\u003e Reverse-scan \u003cem\u003eJ\u003c/em\u003e–\u003cem\u003eV\u003c/em\u003e curves of wide-bandgap (1.68 eV) devices based on different SAMs. \u003cstrong\u003eg)\u003c/strong\u003e Stability under damp-heat storage at 85°C and 85% relative humidity. \u003cstrong\u003eh) \u003c/strong\u003eOperational stability under maximum-power-point tracking at 85°C in N\u003csub\u003e2\u003c/sub\u003e under 1-sun illumination.\u003c/p\u003e","description":"","filename":"Picture4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9432790/v1/53a91aacc84e062c9a96bdbc.jpg"},{"id":108675529,"identity":"a8d21a99-5122-40ca-b18e-890013f2c837","added_by":"auto","created_at":"2026-05-07 08:26:19","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1831781,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9432790/v1/0dde2d2c-3366-4baf-a579-785df31cc679.pdf"},{"id":108675428,"identity":"22d56d05-f45e-48c0-8ac5-a849b77e012d","added_by":"auto","created_at":"2026-05-07 08:26:05","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":23493936,"visible":true,"origin":"","legend":"Supplementary Information","description":"","filename":"SupplementaryInformation.docx","url":"https://assets-eu.researchsquare.com/files/rs-9432790/v1/a4b5a02c291135125dcaf9d0.docx"},{"id":108675464,"identity":"4d948238-8d55-4454-91ee-e0a8892f5949","added_by":"auto","created_at":"2026-05-07 08:26:09","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":17820710,"visible":true,"origin":"","legend":"","description":"","filename":"ExtendedData.docx","url":"https://assets-eu.researchsquare.com/files/rs-9432790/v1/e3a24c0bbb9035539b3c7174.docx"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Geometry-dependent monolayers for efficient inverted perovskite solar cells","fulltext":[{"header":"Introduction","content":"\u003cp\u003eWith the emergence of self-assembled monolayers (SAMs), the design space of inverted perovskite solar cells (PSCs) has substantially redefined by rendering this buried interface molecularly addressable.\u003csup\u003e8-10,13-15\u003c/sup\u003e As molecularly thin hole-selective contacts, SAMs enable favorable work-function tuning, low parasitic absorption, and programmable interfacial properties without requiring a thick doped hole-transport layer,\u003csup\u003e16-19\u003c/sup\u003e pushing certified efficiencies of small-area single-junction perovskite solar cells beyond 27%.\u003csup\u003e20-24\u003c/sup\u003e Their appeal also derives from a modular molecular architecture, in which an anchoring group binds to the electrode surface,\u003csup\u003e25-27\u003c/sup\u003e a linker defines adsorption geometry and packing,\u003csup\u003e28,29\u003c/sup\u003e and a \u0026pi;-conjugated core governs frontier orbital energies and intermolecular electronic coupling.\u003csup\u003e30\u003c/sup\u003e Since anchoring chemistry is largely dictated by oxide surface functionality, and dipole engineering at the anchor is intrinsically coupled to adsorption robustness and molecular order, recent advances have focused predominantly on the \u0026pi;-core,\u003csup\u003e31\u003c/sup\u003e including asymmetric geometries to improve surface coverage,\u003csup\u003e21,32\u003c/sup\u003e extending \u0026pi;-conjugation to tune the highest occupied molecular orbital (HOMO) and interfacial coupling, functional substituents to suppress interfacial traps or strengthen dipoles,\u003csup\u003e8,33\u003c/sup\u003e and rigidified hydrocarbon frameworks to enhance chemical resilience (Extended Data Fig. 1).\u003csup\u003e9,34\u003c/sup\u003e Despite substantial progress, they typically emphasized either robust bottom-interface binding and energetic regulation at the oxide/SAM contact, or top-interface passivation and crystallization control at the SAM/perovskite contact.\u003csup\u003e35,36\u003c/sup\u003e Such a separation is inherently incomplete, as a SAM-based buried contact constitutes a coupled electrode-SAM-perovskite junction, in which interfacial bonding, molecular orientation and packing, and charge transport across the nanometre-scale organic layer are intrinsically linked.\u003csup\u003e11-14\u003c/sup\u003e Emerging evidence further indicates that charge transfer across practical SAM contacts is often governed by thermally activated hopping through localized states, rather than purely coherent tunneling,\u003csup\u003e12\u003c/sup\u003e rendering charge extraction highly sensitive to molecular geometry and interfacial orbital overlap\u0026mdash;parameters not explicitly incorporated into most previous molecular designs. The central challenge, therefore, lies not only in work-function regulating, but in the simultaneous integration of interfacial defect suppression, robust orbital coupling, and low-loss carrier transfer across the molecular contact.\u003c/p\u003e\n\u003cp\u003eHere we establish a geometry-dependent three-layer molecular-contact framework that regards the electrode/SAM interface, the SAM/perovskite interface, and charge transfer across the monolayer as an integrated whole. Using a carbazole-based platform, we incorporate benzothiophene unit into the \u0026pi;-core to construct four regioisomeric architectures and define the geometric origin of interfacial orbital coupling (\u003cstrong\u003eFig. 1a\u003c/strong\u003e and \u003cstrong\u003e1b\u003c/strong\u003e). In this design, the phosphonic-acid anchor ensures robust chemisorption to the oxide anode, whereas the sulfur site acts as a soft Lewis base that binds undercoordinated Pb\u003csup\u003e2+\u003c/sup\u003e species at the perovskite surface,\u003csup\u003e37,38\u003c/sup\u003e affording directional dual-side coupling and constrained molecular orientation within a single SAM. Computation and experiment together identify a geometry-dependent principle: when favorable HOMO alignment is preserved, an N-\u0026pi;-S electronic effect strengthens sulfur-mediated coordination, and an L-shaped backbone that exposes sulfur and nitrogen functionalities toward the perovskite maximizes interfacial orbital overlap while minimizing transport loss. Enabled by reduced defect formation and accelerated charge extraction, DBT34ID-based single-junction PSCs achieves a record high power-conversion efficiency (PCE) of 28.11% (certified 27.78% in reverse-scan model and 27.24% in stabilized output),\u003csup\u003e20-24\u003c/sup\u003e and retains \u0026gt;95% of their initial efficiency after 1,500 hours of maximum-power-point tracking (MPPT) according to ISOS-L-2 aging protocol.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eGeometry-dependent three-layer molecular-contact framework\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe fused-ring topology and geometric configuration of the \u0026pi;-conjugated scaffold in SAM molecules define the HOMO energy, orbital distribution and intrinsic dipole moment, whereas weak \u0026pi;-\u0026pi; interactions between adjacent units offer only limited control over collective solid-state behavior, particularly intermolecular packing and spatial orientation.\u003csup\u003e13\u003c/sup\u003e Notably, in molecularly thin hole-selective contacts, the orientation of the \u0026pi;-conjugated backbone further governs orbital coupling with both adjacent interfaces and is therefore intrinsically linked to molecular geometry.\u003csup\u003e10\u003c/sup\u003e To correlate molecular geometry with interfacial charge-transfer kinetics, we adopted a dual-anchoring design guided by hard-soft acid-base principles: a phosphonic-acid headgroup chemisorbs to hydroxylated ITO, whereas a sulfur site embedded in the \u0026pi;-conjugated core binds undercoordinated Pb\u0026sup2;⁺ at the perovskite surface, establishing bidirectional chemical coupling within a single molecular layer. We select a benzothienocarbazole motif as the \u0026pi;-scaffold because it affords calculated HOMO energies of -5.52 to -5.76 eV, well aligned with typical perovskite valence bands (\u003cem\u003eE\u003c/em\u003e\u003csub\u003eV\u003c/sub\u003e), while allowing regioisomeric variation for geometric control (\u003cstrong\u003eFig. 1b\u003c/strong\u003e). Single-molecule calculations show HOMOs delocalized across the conjugated framework (Supplementary Fig. S31), consistent with continuous intramolecular hopping pathways. Electrostatic-potential (ESP) maps further localized negative potential at the sulfur site, and an N-\u0026pi;-S electronic effect rendered DBT34ID and DBT32ID the most nucleophilic isomers (ESP minima of about -21.4 kcal mol\u003csup\u003e-1\u003c/sup\u003e), indicating an enhanced propensity for Pb coordination.\u003c/p\u003e\n\u003cp\u003eTo translate this design into practical hole-selective contacts, we constructed a three-layer molecular-contact framework in which the electrode-SAM-perovskite junction is treated as an integrated whole. Following the device fabrication sequence, phosphonate chemisorption on hydroxylated ITO was considered first, after which a defect-bearing perovskite fragment was introduced near the SAM \u0026pi;-terminus. Multidimensional energy scans were then used to optimize the binding site, tilt angle, and lateral orientation. The simulations reveal a pronounced geometric dependence of interfacial contact (\u003cstrong\u003eFig. 1c\u003c/strong\u003e). The linear isomer DBT32ID preferentially adopts a substrate-parallel configuration with a large \u0026pi;-terminal-oxide separation (d\u003csub\u003e\u0026pi;\u0026middot;\u0026middot;\u0026middot;A\u003c/sub\u003e \u0026asymp; 7.6 \u0026Aring;). The obtuse-angle L-shaped isomers DBT21ID and DBT43ID reduce this distance to 5.9 and 6.1 \u0026Aring;, respectively, whereas the acute-angle L-shaped isomer DBT34ID projects the conjugated core towards the substrate, shortening d\u003csub\u003e\u0026pi;\u0026middot;\u0026middot;\u0026middot;A\u003c/sub\u003e to about 3.3 \u0026Aring;. Such a reduced d\u003csub\u003e\u0026pi;\u0026middot;\u0026middot;\u0026middot;A\u003c/sub\u003e distance maximizes frontier-orbital overlap of the \u0026pi;-scaffold across both interfaces and thus favors more efficient interfacial charge-transfer kinetics for PCE optimization. Together, this geometry-dependent three-layer molecular-contact framework defines a transferable design principle for SAMs that integrates oxide binding, perovskite coordination, and transport-efficient interfacial coupling.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eInterfacial modification and charge extraction dynamics\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe primary role of a hole-selective SAM is to raise the work function (WF) of the bottom electrode and position its HOMO appropriately with respect to the perovskite \u003cem\u003eE\u003c/em\u003e\u003csub\u003eV\u003c/sub\u003e, thereby enabling efficient hole extraction across the buried contact.\u003csup\u003e18\u003c/sup\u003e Ultraviolet photoelectron spectroscopy (UPS) shows that all four phosphonic-acid SAMs increase the WF of ITO by 1.14 to 1.31 eV relative to bare ITO (\u003cstrong\u003eFig. 2a\u003c/strong\u003e), confirming strong interfacial dipole modulation. Among them, DBT21ID yields a Fermi level (\u003cem\u003eE\u003c/em\u003e\u003csub\u003eF\u003c/sub\u003e = -4.84 eV) closest to that of the perovskite (-4.75 eV), whereas DBT32ID exhibits the largest offset (\u003cem\u003eE\u003c/em\u003e\u003csub\u003eF\u003c/sub\u003e = -5.11 eV), consistent with its linear conjugated geometry, which favors\u0026nbsp;a more substrate-parallel and laterally displaced adsorption configuration. According the UPS-derived valence-band maxima (VBM), the surface \u003cem\u003eE\u003c/em\u003e\u003csub\u003eV\u003c/sub\u003e values of the SAM-modified ITO substrates were estimated to lie between\u0026nbsp;-5.42\u0026nbsp;and\u0026nbsp;-5.53\u0026nbsp;eV (\u003cstrong\u003eFig. 2b\u003c/strong\u003e), approaching to the intrinsic perovskite \u003cem\u003eE\u003c/em\u003e\u003csub\u003eV\u003c/sub\u003e of\u0026nbsp;-5.65\u0026nbsp;eV (Supplementary Fig. S39). The resulting small offsets (\u0026Delta;\u003cem\u003eE\u003c/em\u003e\u003csub\u003eV\u003c/sub\u003e \u0026lt;0.23 eV) indicate favorable energetic alignment for hole extraction and reduced interfacial voltage loss (\u003cstrong\u003eFig. 2c\u003c/strong\u003e).\u003csup\u003e39\u003c/sup\u003e Notably, the \u003cem\u003eE\u003c/em\u003e\u003csub\u003eV\u003c/sub\u003e positions of the adsorbed SAMs deviate from the HOMO trend established by density functional theory and cyclic voltammetry for the isolated molecules (Supplementary Fig. S34). Although DBT32ID possesses the shallowest HOMO, it gives the deepest \u003cem\u003eE\u003c/em\u003e\u003csub\u003eV\u003c/sub\u003e on ITO, whereas DBT34ID, with a substantially deeper isolated-molecule HOMO, exhibits the shallowest \u003cem\u003eE\u003c/em\u003e\u003csub\u003eV\u003c/sub\u003e after adsorption. This contrast discloses that interfacial energetics are governed not only by molecular frontier levels, but also by adsorption-induced WF modulation, orbital hybridization, and packing-induced electronic delocalization. Accordingly, DBT32ID primarily maximizes the WF increase of ITO, whereas DBT34ID promotes stronger \u0026pi;-framework-ITO coupling and tighter packing, leading to greater interfacial delocalization and a higher \u003cem\u003eE\u003c/em\u003e\u003csub\u003eV\u003c/sub\u003e position.\u003c/p\u003e\n\u003cp\u003eTo further verify orbital coupling and spatial proximity between ITO and the adsorbed SAMs, we calculate electron-density-difference (EDD) plots for the optimized SAM/ITO interfaces within the geometry-dependent three-layer molecular-contact framework (\u003cstrong\u003eFig. 2d\u003c/strong\u003e and Supplementary Fig. S33). Although the four isomers share the same sulfur-containing fused heteroaromatic scaffold, their distinct geometries produce markedly different interfacial coupling. DBT34ID, which exhibits the shortest \u003cem\u003ed\u003c/em\u003e\u003csub\u003e\u0026pi;\u003c/sub\u003e\u003csub\u003e⋯A\u003c/sub\u003e distance to ITO, reflecting the strongest density redistribution at the SAM/ITO junction,\u003csup\u003e40-42\u003c/sup\u003e consistent with the largest interfacial orbital overlap. By contrast, other benzothienocarbazole (BTCz) isomers, such as DBT21ID, exhibit much weaker coupling due to their larger interfacial separation. Given the comparable effective conjugation areas of the four isomers, and charge transport in amorphous organic aggregates is generally dominated by intermolecular hopping, the combined UPS and EDD results identify interfacial geometry as the dominant factor governing vertical charge transfer, with DBT34ID providing the most favorable configuration. Conductive atomic force microscopy (C-AFM) further supports this interpretation. All SAMs uniformly cover ITO and form continuous conductive pathways, indicating homogeneous monolayer formation, yet DBT34ID delivers nearly an order-of-magnitude higher current than DBT21ID (\u003cstrong\u003eFig. 2e\u003c/strong\u003e and Extended Data Fig. 2a), evidencing substantially lower vertical transport resistance.\u003csup\u003e1,5,43\u003c/sup\u003e We next examined charge-transfer dynamics after perovskite deposition by femtosecond transient absorption (fs-TA) spectroscopy. Because optical absorption is dominated by the thick perovskite layer, the signal primarily reflects bulk-dominated carrier dynamics on the sub-nanosecond timescale. The fitted average decay lifetime (\u003cem\u003e\u0026tau;\u003c/em\u003e\u003csub\u003eavg\u003c/sub\u003e) follows the order DBT34ID \u0026gt; DBT21ID \u003cstrong\u003e(Fig. 2f\u003c/strong\u003e and \u003cstrong\u003e2g\u003c/strong\u003e), consistent with progressively improved interfacial passivation, reduced defect-assisted recombination, and suppressed non-radiative decay.\u003csup\u003e11\u003c/sup\u003e Time-resolved photoluminescence (TRPL) measurements provides an independent assessment. On insulating quartz, where interfacial extraction is negligible, all SAM-treated films show longer photoluminescence lifetimes than the SAM-free control (Supplementary, Fig. S36), and DBT34ID produces the largest increase (\u003cstrong\u003eFig. 2h\u003c/strong\u003e), indicating the most effective defect suppression. On ITO, by contrast, where hole extraction is operative, the lifetimes become strongly SAM-dependent and decrease most markedly for DBT34ID (\u003cstrong\u003eFig. 2i\u003c/strong\u003e), corroborating the fastest interfacial charge extraction.\u003csup\u003e40\u003c/sup\u003e Together, these results suggest that DBT34ID provide the most favorable combination of energetic alignment, interfacial orbital coupling, defect suppression, and carrier-transfer kinetics.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eInterfacial chemical passivation and perovskite morphology\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eX-ray photoelectron spectroscopy (XPS) identifies the chemical origin of the different passivation strengths. Relative to pristine perovskite, DBT34ID shifts the Pb 4f envelope to lower binding energy by ~0.21 eV and narrows its linewidth, consistent with Pb-S coordination and a reduced density of undercoordinated Pb-related defect states at the buried interface,\u003csup\u003e37\u003c/sup\u003e whereas DBT21ID induces only marginal changes (\u003cstrong\u003eFig. 3a\u003c/strong\u003e). Complementary evidence is provided by the S 2p spectra: after contact with perovskite, DBT34ID shows a clear shift to higher binding energy (~0.17 eV), further supporting sulfur involvement in interfacial Pb binding,\u003csup\u003e37\u003c/sup\u003e whereas DBT21ID shows negligible perturbation (\u003cstrong\u003eFig. 3b\u003c/strong\u003e). Fourier-transform infrared spectroscopy further supports this assignment,\u003csup\u003e38\u003c/sup\u003e with DBT34ID showing a more pronounced change in the relative intensity of the C-S stretching vibration, together with slight band broadening, after perovskite deposition. (Supplementary Fig. S38). Together, these results indicate stronger sulfur-mediated coordination to Pb-related defect sites for DBT34ID. This stronger dual-side coupling also influences perovskite crystallization. Surface Scanning electron microscope (SEM) reveals a clear morphological contrast among the SAMs (\u003cstrong\u003eFig. 3c\u003c/strong\u003e and Extended Data Fig. 2b). Perovskite film grown on DBT21ID exhibits frequent pinholes and nanovoids, indicative of incomplete grain coalescence and a higher density of buried interfacial defects.\u003csup\u003e44,45\u003c/sup\u003e In contrast, DBT34ID yields a compact, uniformly fused grain network with essentially void-free coverage. Cross-sectional SEM further shows that DBT34ID produces a flatter and more continuous buried interface, a denser and more uniform perovskite layer, and fewer interfacial voids than DBT21ID, affording improved contact quality and structural integrity.\u003csup\u003e17,46,47\u003c/sup\u003e Atomic force microscopy demonstrates similar surface roughness for all SAM-treated films (Rq \u0026asymp; 28 to 31 nm), reflecting that these differences arose primarily from defect morphology rather than global topographic roughness (Supplementary Fig. S41 and S42).\u003csup\u003e48\u003c/sup\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn addition to the morphology, different SAMs also greatly affects the crystallinity of perovskite films, which is corroborated with these structural differences (\u003cstrong\u003eFig. 3d\u003c/strong\u003e). From Grazing-incidence wide-angle x-ray scattering (GIWAXS), perovskite on DBT21ID shows broad, weak Debye\u0026ndash;Scherrer rings with a pronounced diffuse background, consistent with greater microstructural disorder and smaller coherent scattering domains. By contrast, DBT34ID produces sharper and more intense Bragg features, a higher peak-to-background ratio, and clearly higher-\u003cem\u003eq\u003c/em\u003e reflections, indicating improved crystallinity and reduced defect-associated diffuse scattering.\u003csup\u003e44,48\u003c/sup\u003e Its more anisotropic azimuthal intensity distribution also suggests a higher degree of preferred orientation. However, conventional GIWAXS and X-Ray Diffraction reveal only marginal differences among the films, indicating that DBT34ID enhances crystallographic order, orientational distribution, and local packing quality without fundamentally altering the crystalline phase (Extended Data Fig. 3).\u003csup\u003e49\u003c/sup\u003e These structural differences are further reflected in the optical response. PL mapping revealed that DBT34ID yielded stronger and more spatially uniform emission, with fewer low-intensity domains, consistent with reduced trap-assisted nonradiative recombination and improved film homogeneity (\u003cstrong\u003eFig. 3e\u003c/strong\u003e).\u003csup\u003e38\u003c/sup\u003e Steady-state PL measurements showed the same trend, with DBT34ID delivering a much stronger PL enhancement than DBT21ID, consistent with more effective suppression of Shockley\u0026ndash;Read\u0026ndash;Hall recombination. (Extended Data Fig. 4).\u003csup\u003e50\u003c/sup\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003ePhotovoltaics performance and stability\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConsistent with its more favorable orbital coupling, stronger sulfur-mediated passivation, and reduced transport loss at the buried contact, DBT34ID delivered the best performance in devices with the architecture ITO/DBT-derivative SAMs/perovskite/1,3-diaminopropane dihydroiodide (PDADI)/\u0026nbsp;fullerene (C\u003csub\u003e60\u003c/sub\u003e)/ bathocuproine (BCP)/Ag (\u003cstrong\u003eFig. 4a\u003c/strong\u003e). The champion 0.050-cm\u0026sup2; device achieved a PCE of 28.11% (27.78% certified by the National PV Industry Measurement and Testing Center; \u003cstrong\u003eFig. 4b\u003c/strong\u003e) with negligible hysteresis, enabled by concurrent improvements in open-circuit voltage (\u003cem\u003eV\u003c/em\u003e\u003csub\u003eOC\u003c/sub\u003e, 1.21 V), short-circuit current density (\u003cem\u003eJ\u003c/em\u003e\u003csub\u003eSC\u003c/sub\u003e, 26.75 mA cm\u003csup\u003e-\u003c/sup\u003e\u0026sup2;), and fill factor (FF, 86.69%), thereby establishing a new benchmark for single-junction PSCs.\u003csup\u003e20,23\u003c/sup\u003e The steady output of the champion device also reaches 27.84% (27.24% certified by the National PV Industry Measurement and Testing Center; Supplementary Fig. S43), representing the highest reported steady-state PCE.\u003csup\u003e21\u003c/sup\u003e To maximize photocurrent, we introduced an evaporated MgF\u003csub\u003e2\u003c/sub\u003e antireflection coating for optical management, and the resulting enhancement in light harvesting was confirmed by external quantum efficiency measurements, which yielded an integrated \u003cem\u003eJ\u003c/em\u003e\u003csub\u003eSC\u003c/sub\u003e of 25.66 mA cm\u003csup\u003e-2\u003c/sup\u003e (\u003cstrong\u003eFig. 4c\u003c/strong\u003e). By comparison, the other regioisomers delivered lower champion PCEs of 26.52% for DBT21ID, 27.17% for DBT32ID, and 27.28% for DBT43ID. DBT34ID-based devices also exhibited the narrowest PCE distribution (\u003cstrong\u003eFig. 4d\u003c/strong\u003e), indicating that the optimized molecular geometry improves not only peak efficiency but also device reproducibility.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe performance advantage of DBT34ID is maintained across device formats relevant to practical deployment. In 1-cm\u003csup\u003e2\u003c/sup\u003e devices, DBT34ID achieved a champion PCE of 25.28%, with a \u003cem\u003eV\u003c/em\u003e\u003csub\u003eOC\u003c/sub\u003e of 1.163 V, a \u003cem\u003eJ\u003c/em\u003e\u003csub\u003eSC\u003c/sub\u003e of 25.55 mA cm\u003csup\u003e\u0026minus;\u003c/sup\u003e\u003csup\u003e2\u003c/sup\u003e, and an FF of 85.06%, outperforming DBT21ID (24.76%), DBT32ID (24.59%), and DBT43ID (25.06%) (\u003cstrong\u003eFig. 4e\u003c/strong\u003e and Extended Data Table 1). To evaluate its applicability to tandem photovoltaics, we further examined wide-bandgap devices based on a 1.68\u0026nbsp;eV perovskite absorber. DBT34ID\u0026nbsp;based device\u0026nbsp;again gives\u0026nbsp;the best result, delivering a champion PCE of 24.99%, with a \u003cem\u003eV\u003c/em\u003e\u003csub\u003eOC\u003c/sub\u003e of 1.257 V, a \u003cem\u003eJ\u003c/em\u003e\u003csub\u003eSC\u003c/sub\u003e of 23.37 mA cm\u003csup\u003e\u0026minus;2\u003c/sup\u003e, and an FF of 85.02%, compared with 24.02% for DBT21ID, 23.38% for DBT32ID, and 24.44% for DBT43ID (\u003cstrong\u003eFig. 4f\u003c/strong\u003e). The retention of this performance hierarchy across active area and bandgap indicates that the benefit of DBT34ID is not device-specific, but originates from a more general improvement in buried-contact quality.\u0026nbsp;We next evaluate device stability under multiple aging protocols. Under damp-heat aging at 85\u0026deg;C and 85% relative humidity with encapsulation (ISOS-D-3, 10 devices), DBT34ID-based devices retained about 95.1% of their initial efficiency after\u0026nbsp;~1,000 hours, compared with 84.8% for DBT21ID, 91.0% for DBT32ID, and\u0026nbsp;92.6% for DBT43ID (\u003cstrong\u003eFig. 4\u003c/strong\u003e\u003cstrong\u003eg\u003c/strong\u003e). Under continuous maximum-power-point tracking at\u0026nbsp;65\u0026deg;C under 100 mW cm\u003csup\u003e\u0026minus;\u003c/sup\u003e\u003csup\u003e2\u003c/sup\u003e illumination in N\u003csub\u003e2\u003c/sub\u003e (ISOS-L-2), DBT34ID-based devices retained about 95.2% of their initial efficiency after\u0026nbsp;~1,500 hours, whereas DBT21ID-, DBT32ID-, and DBT43ID-based devices decreased to about 82.8%, 88.7%, and 91.0%, respectively (\u003cstrong\u003eFig. 4h\u003c/strong\u003e). We attribute this enhanced operational stability to the optimized interfacial configuration of DBT34ID, which preserves a kinetically efficient and chemically resilient buried contact under prolonged bias, illumination, and thermal stress.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eOur results identify the buried contact in inverted PSCs as an integrated electrode-SAM-perovskite junction and define a geometry-dependent three-layer molecular-contact framework that links molecular binding geometry to interfacial energetics, defect passivation and charge-transfer kinetics. Within the BTCz platform, regioisomeric control reveals a clear geometry-function relationship: reinforced by an N-\u0026pi;-S electronic motif, the embedded sulfur site strengthens coordination to defective Pb\u0026sup2;⁺, whereas the acute-angled L-shaped geometry projects the sulfur and nitrogen functionalities towards the perovskite while preserving efficient orbital overlap across the buried junction. This geometry-dependent coupling simultaneously strengthens defect passivation and vertical charge transfer, leading to improved interfacial order, reduced non-radiative recombination, faster charge extraction, and concurrent gains in efficiency and operational stability. More broadly, these findings establish a transferable design principle for SAM-based buried contacts: high performance arises from the integration of chemical functionality with molecular geometries that enable efficient interfacial coupling and charge transfer. Transport-aware dual-side coupling thus provides a molecular design route to higher-performance inverted PSCs and scalable single-junction and tandem perovskite photovoltaics.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAuthor Contributions\u003c/p\u003e\n\u003cp\u003eX.Y. conceived the original idea. X.C., J.X. and M.Y. carried out the molecular synthesis, structural characterization and optimization of the experimental protocols under the supervision of X.Y. and C.Y. Perovskite films and devices were fabricated by S.Y., B.X. Y.S., X.L., Z.W., Z.S. and B.Z. under the supervision of H.Y. and Z.O. Data analysis and discussion were performed by C.Z., T.Z. and X.Y. Theoretical calculations were performed by C.Z. and X.Y. under the supervision of C.Y. X.Y. wrote the manuscript, with revisions from T.Z. and C.Y. All authors discussed the results and commented on the manuscript. C.Y. supervised the project.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data supporting the findings of this study are available within the Article and its Supplementary Information. Source data are available from the corresponding authors upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research was financially supported by the National Natural Science Foundation of China (Nos. 22575155 and 52503337), Guangdong Basic and Applied Basic Research Foundation (Nos. 2024A1515010744), the Shenzhen Science and Technology Program (ZDSYS20210623091813040) and the Research Team Cultivation Program of Shenzhen University (2023DFT004). Open Research Fund of State Key Laboratory of Photovoltaic Science and Technology (No. PVST252208). The authors also thank the Instrumental Analysis Center of Shenzhen University for analytical support.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eLi, Q.\u003cem\u003e et al.\u003c/em\u003e Graphene-polymer reinforcement of perovskite lattices for durable solar cells. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e387\u003c/strong\u003e, 1069-1077 (2025).\u003c/li\u003e\n\u003cli\u003eLiu, S.\u003cem\u003e et al.\u003c/em\u003e Buried interface molecular hybrid for inverted perovskite solar cells. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e632\u003c/strong\u003e, 536-542 (2024).\u003c/li\u003e\n\u003cli\u003eLiang, Y.\u003cem\u003e et al.\u003c/em\u003e A matrix-confined molecular layer for perovskite photovoltaic modules. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e648\u003c/strong\u003e, 91-96 (2025).\u003c/li\u003e\n\u003cli\u003eJiang, W.\u003cem\u003e et al.\u003c/em\u003e Toughened self-assembled monolayers for durable perovskite solar cells. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e646\u003c/strong\u003e, 95-101 (2025).\u003c/li\u003e\n\u003cli\u003eJia, L.\u003cem\u003e et al.\u003c/em\u003e Efficient perovskite/silicon tandem with asymmetric self-assembly molecule. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e644\u003c/strong\u003e, 912-919 (2025).\u003c/li\u003e\n\u003cli\u003eLi, G.\u003cem\u003e et al.\u003c/em\u003e Stabilizing high-efficiency perovskite solar cells via strategic interfacial contact engineering. \u003cem\u003eNat. Photonics\u003c/em\u003e \u003cstrong\u003e20\u003c/strong\u003e, 55-62 (2025).\u003c/li\u003e\n\u003cli\u003eWu, W.\u003cem\u003e et al.\u003c/em\u003e Stable and uniform self-assembled organic diradical molecules for perovskite photovoltaics. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e389\u003c/strong\u003e, 195-199 (2025).\u003c/li\u003e\n\u003cli\u003eLi, Z.\u003cem\u003e et al.\u003c/em\u003e Stabilized hole-selective layer for high-performance inverted p-i-n perovskite solar cells. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e382\u003c/strong\u003e, 284-289 (2023).\u003c/li\u003e\n\u003cli\u003eZhao, K.\u003cem\u003e et al.\u003c/em\u003e peri-Fused polyaromatic molecular contacts for perovskite solar cells. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e632\u003c/strong\u003e, 301-306 (2024).\u003c/li\u003e\n\u003cli\u003eLi, T.\u003cem\u003e et al.\u003c/em\u003e Tin-based perovskite solar cells with a homogeneous buried interface. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e648\u003c/strong\u003e, 84-90 (2025).\u003c/li\u003e\n\u003cli\u003eYang, W.\u003cem\u003e et al.\u003c/em\u003e Axially chiral molecular contacts with low isomerization barriers for perovskite solar cells. \u003cem\u003eNat. Photonics\u003c/em\u003e, DOI: 10.1038/s41566-41025-01817-41568 (2026).\u003c/li\u003e\n\u003cli\u003eFang, F.\u003cem\u003e et al.\u003c/em\u003e Electron hopping in conjugated molecular wires with application to solar cells. \u003cem\u003eNat. Chem.\u003c/em\u003e \u003cstrong\u003e18\u003c/strong\u003e, 756\u0026ndash;764 (2026).\u003c/li\u003e\n\u003cli\u003eLi, T.\u003cem\u003e et al.\u003c/em\u003e Quasi-random oriented molecular contacts for inverted perovskite solar cells with improved efficiency. \u003cem\u003eNat. Energy\u003c/em\u003e, DOI: 10.1038/s41560-41026-02024-41567 (2026).\u003c/li\u003e\n\u003cli\u003ePeng, C.\u003cem\u003e et al.\u003c/em\u003e Strengthened Perovskite/SAM Heterointerface for Stable Perovskite Solar Cells. \u003cem\u003eJ. Am. Chem. Soc.\u003c/em\u003e \u003cstrong\u003e147\u003c/strong\u003e, 48391-48399 (2025).\u003c/li\u003e\n\u003cli\u003eHan, P. \u0026amp; Zhang, Y. Recent Advances in Carbazole‐Based Self‐Assembled Monolayer for Solution‐Processed Optoelectronic Devices. \u003cem\u003eAdv. Mater.\u003c/em\u003e \u003cstrong\u003e36\u003c/strong\u003e, 2405630 (2024).\u003c/li\u003e\n\u003cli\u003eZhang, S.\u003cem\u003e et al.\u003c/em\u003e Minimizing buried interfacial defects for efficient inverted perovskite solar cells. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e380\u003c/strong\u003e, 404-409 (2023).\u003c/li\u003e\n\u003cli\u003eTan, Q.\u003cem\u003e et al.\u003c/em\u003e Inverted perovskite solar cells using dimethylacridine-based dopants. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e620\u003c/strong\u003e, 545-551 (2023).\u003c/li\u003e\n\u003cli\u003eShin, S. S.\u003cem\u003e et al.\u003c/em\u003e Interlayer engineering in metal halide perovskite photovoltaics. \u003cem\u003eNat. Photonics\u003c/em\u003e \u003cstrong\u003e20\u003c/strong\u003e, 11-23 (2026).\u003c/li\u003e\n\u003cli\u003eMorales, C. A. F.\u003cem\u003e et al.\u003c/em\u003e Multilayer Formation, Interfacial Binding, and Stability of Self-Assembled Molecules in Perovskite Solar Cells. \u003cem\u003eJ. Am. Chem. Soc.\u003c/em\u003e \u003cstrong\u003e147\u003c/strong\u003e, 48136-48146 (2025).\u003c/li\u003e\n\u003cli\u003eXiong, Z.\u003cem\u003e et al.\u003c/em\u003e Homogenized chlorine distribution for \u0026amp;gt;27% power conversion efficiency in perovskite solar cells. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e390\u003c/strong\u003e, 638-642 (2025).\u003c/li\u003e\n\u003cli\u003eTian, C.\u003cem\u003e et al.\u003c/em\u003e Photostable donor\u0026ndash;acceptor interface for minimizing energy loss in inverted perovskite solar cells. \u003cem\u003eNat. Photonics\u003c/em\u003e, DOI: 10.1038/s41566-41025-01827-41566 (2026).\u003c/li\u003e\n\u003cli\u003eZhang, Z.\u003cem\u003e et al.\u003c/em\u003e Photoswitchable isomers to improve grain boundary resilience and perovskite solar cells stability under light cycling. \u003cem\u003eNat. Energy\u003c/em\u003e, DOI: 10.1038/s41560-41026-01993-z (2026).\u003c/li\u003e\n\u003cli\u003eYang, Y.\u003cem\u003e et al.\u003c/em\u003e Molecular Buffering Regulates Lattice Strain for Fatigue‐Resistant Perovskite Photovoltaics Under Cryogenic Thermal Cycling. \u003cem\u003eAdv. Mater.\u003c/em\u003e \u003cstrong\u003e38\u003c/strong\u003e, e19339 (2026).\u003c/li\u003e\n\u003cli\u003eLu, H.\u003cem\u003e et al.\u003c/em\u003e Ion‐Defect Dual Management for Achieving Efficient Air‐Processed Perovskite Solar Cells With Certified Efficiency 27.1%. \u003cem\u003eAdv. Mater.\u003c/em\u003e \u003cstrong\u003e38\u003c/strong\u003e, e17596 (2026).\u003c/li\u003e\n\u003cli\u003eFei, C.\u003cem\u003e et al.\u003c/em\u003e Limiting phosphonic acid interlayer\u0026ndash;perovskite reactivity to stabilize perovskite solar modules. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e391\u003c/strong\u003e, eadz7969 (2026).\u003c/li\u003e\n\u003cli\u003eLuo, C.\u003cem\u003e et al.\u003c/em\u003e Engineering bonding sites enables uniform and robust self-assembled monolayer for stable perovskite solar cells. \u003cem\u003eNat. Mater.\u003c/em\u003e \u003cstrong\u003e24\u003c/strong\u003e, 1265-1272 (2025).\u003c/li\u003e\n\u003cli\u003eWang, J.\u003cem\u003e et al.\u003c/em\u003e Less-acidic boric acid-functionalized self-assembled monolayer for mitigating NiOx corrosion for efficient all-perovskite tandem solar cells. \u003cem\u003eNat. Commun.\u003c/em\u003e \u003cstrong\u003e16\u003c/strong\u003e, 4148 (2025).\u003c/li\u003e\n\u003cli\u003eYang, J.\u003cem\u003e et al.\u003c/em\u003e Flexibility meets rigidity: a self-assembled monolayer materials strategy for perovskite solar cells. \u003cem\u003eNat. Commun.\u003c/em\u003e \u003cstrong\u003e16\u003c/strong\u003e, 6968 (2025).\u003c/li\u003e\n\u003cli\u003eWang, D.\u003cem\u003e et al.\u003c/em\u003e Rigid molecules anchoring on NiOx enable \u0026gt;26% efficiency perovskite solar cells. \u003cem\u003eJoule\u003c/em\u003e \u003cstrong\u003e9\u003c/strong\u003e, 101815 (2025).\u003c/li\u003e\n\u003cli\u003eQu, G.\u003cem\u003e et al.\u003c/em\u003e Self-assembled materials with an ordered hydrophilic bilayer for high performance inverted Perovskite solar cells. \u003cem\u003eNat. Commun.\u003c/em\u003e \u003cstrong\u003e16\u003c/strong\u003e, 86 (2025).\u003c/li\u003e\n\u003cli\u003eYuan, L.\u003cem\u003e et al.\u003c/em\u003e Perovskite Solar Cells and Light Emitting Diodes: Materials Chemistry, Device Physics and Relationship. \u003cem\u003eChem. Rev.\u003c/em\u003e \u003cstrong\u003e125\u003c/strong\u003e, 5057-5162 (2025).\u003c/li\u003e\n\u003cli\u003eWang, J.\u003cem\u003e et al.\u003c/em\u003e Asymmetric Self‐Assembled Molecule With High Dipole Moment for Efficient Wide‐Bandgap Perovskite Solar Cells and Tandems. \u003cem\u003eAdv. Mater.\u003c/em\u003e \u003cstrong\u003e38\u003c/strong\u003e, e23338 (2026).\u003c/li\u003e\n\u003cli\u003eZhu, H.\u003cem\u003e et al.\u003c/em\u003e Improved Hole‐Selective Contact Enables Highly Efficient and Stable FAPbBr3 Perovskite Solar Cells and Semitransparent Modules. \u003cem\u003eAdv. Mater.\u003c/em\u003e \u003cstrong\u003e36\u003c/strong\u003e, 2406872 (2024).\u003c/li\u003e\n\u003cli\u003eLuo, Y.\u003cem\u003e et al.\u003c/em\u003e Bulk nano-heterointerface secures molecular contacts in perovskite solar cells. \u003cem\u003eNat. Mater.\u003c/em\u003e, DOI: 10.1038/s41563-41026-02546-41561 (2026).\u003c/li\u003e\n\u003cli\u003eWang, D.\u003cem\u003e et al.\u003c/em\u003e Self-assembled molecules with hydrogen-bond networks enable efficient all-perovskite tandem solar cells. \u003cem\u003eNat. Energy\u003c/em\u003e \u003cstrong\u003e11\u003c/strong\u003e, 436-448 (2026).\u003c/li\u003e\n\u003cli\u003eGao, D.\u003cem\u003e et al.\u003c/em\u003e Autonomous closed-loop framework for reproducible perovskite solar cells. \u003cem\u003eNature\u003c/em\u003e (2026).\u003c/li\u003e\n\u003cli\u003eYao, S.\u003cem\u003e et al.\u003c/em\u003e Sulfur‐Modulated Fully‐Conjugated Self‐Assembled Monolayers for Synergistic Dual‐Interface Optimization in Inverted Perovskite Solar Cells. \u003cem\u003eAngew. Chem. Int. Ed.\u003c/em\u003e, DOI: 10.1002/anie.5319815 (2026).\u003c/li\u003e\n\u003cli\u003eShao, G.\u003cem\u003e et al.\u003c/em\u003e Reducing Interface Energy Loss of Perovskite Solar Cells by Molecular Engineering of Hole‐Transporting Materials. \u003cem\u003eAngew. Chem. Int. Ed.\u003c/em\u003e \u003cstrong\u003e65\u003c/strong\u003e, e23799 (2026).\u003c/li\u003e\n\u003cli\u003ePark, S. M.\u003cem\u003e et al.\u003c/em\u003e Low-loss contacts on textured substrates for inverted perovskite solar cells. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e624\u003c/strong\u003e, 289-294 (2023).\u003c/li\u003e\n\u003cli\u003eChen, H.\u003cem\u003e et al.\u003c/em\u003e Improved charge extraction in inverted perovskite solar cells with dual-site-binding ligands. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e384\u003c/strong\u003e, 189-193 (2024).\u003c/li\u003e\n\u003cli\u003eLi, M.\u003cem\u003e et al.\u003c/em\u003e A molecularly engineered electron-selective self-assembled monolayer enhances quasi-Fermi level splitting in inverted perovskite solar cells. \u003cem\u003eNat. Energy\u003c/em\u003e, DOI: 10.1038/s41560-41026-02025-41566 (2026).\u003c/li\u003e\n\u003cli\u003eDong, B.\u003cem\u003e et al.\u003c/em\u003e Self-assembled bilayer for perovskite solar cells with improved tolerance against thermal stresses. \u003cem\u003eNat. Energy\u003c/em\u003e \u003cstrong\u003e10\u003c/strong\u003e, 342-353 (2025).\u003c/li\u003e\n\u003cli\u003eFeng, K.\u003cem\u003e et al.\u003c/em\u003e Non-fullerene electron-transporting materials for high-performance and stable perovskite solar cells. \u003cem\u003eNat. Mater.\u003c/em\u003e \u003cstrong\u003e24\u003c/strong\u003e, 770-777 (2025).\u003c/li\u003e\n\u003cli\u003eHu, J.\u003cem\u003e et al.\u003c/em\u003e Molecular press annealing enables robust perovskite solar cells. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e391\u003c/strong\u003e, 164-170 (2026).\u003c/li\u003e\n\u003cli\u003ePeng, J.\u003cem\u003e et al.\u003c/em\u003e Maximizing perovskite electroluminescence with ordered 3D/2D heterojunction. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e651\u003c/strong\u003e, 76-82 (2026).\u003c/li\u003e\n\u003cli\u003eWang, Y.\u003cem\u003e et al.\u003c/em\u003e Improved solvent systems for commercially viable perovskite photovoltaic modules. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e390\u003c/strong\u003e, 1021-1028 (2025).\u003c/li\u003e\n\u003cli\u003eLi, X.\u003cem\u003e et al.\u003c/em\u003e Multimodal electron microscopy of halide perovskite interfacial dynamics. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e651\u003c/strong\u003e, 614-620 (2026).\u003c/li\u003e\n\u003cli\u003eChang, X.\u003cem\u003e et al.\u003c/em\u003e Multivalent ligands regulate dimensional engineering for inverted perovskite solar modules. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e391\u003c/strong\u003e, 153-159 (2026).\u003c/li\u003e\n\u003cli\u003eLi, S.\u003cem\u003e et al.\u003c/em\u003e High-efficiency and thermally stable FACsPbI3 perovskite photovoltaics. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e635\u003c/strong\u003e, 82-88 (2024).\u003c/li\u003e\n\u003cli\u003eLiu, S.\u003cem\u003e et al.\u003c/em\u003e Solvated-intermediate-driven surface transformation of lead halide perovskites. \u003cem\u003eNat. Energy\u003c/em\u003e \u003cstrong\u003e11\u003c/strong\u003e, 109\u0026ndash;120 (2026).\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003eMaterials:\u0026nbsp;\u003c/strong\u003eUnless otherwise noted, all reagents and solvents were used as received without further purification. Anhydrous \u003cem\u003eN,N\u003c/em\u003e-dimethylformamide (DMF, 99.8%), dimethyl sulfoxide (DMSO, 99.9%), ethanol (EtOH, 99.5%) and chlorobenzene (CB, 99.8%) were purchased from Advanced Election Technology Co., Ltd., whereas isopropanol (IPA, 99.5%) was purchased from Aladdin. Lead iodide (PbI\u003csub\u003e2\u003c/sub\u003e) was purchased from TCI. Other perovskite precursor materials, including formamidinium iodide (FAI), cesium iodide (CsI), methylammonium iodide (MAI) and methylammonium chloride (MACl), together with C\u003csub\u003e60\u003c/sub\u003e and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), were purchased from Xi\u0026rsquo;an Yuri Solar Co., Ltd., China. Key synthetic intermediates, including 5\u003cem\u003eH\u003c/em\u003e-benzo[4,5]thieno[3,2-\u003cem\u003ec\u003c/em\u003e]carbazole, 11\u003cem\u003eH\u003c/em\u003e-benzo[4,5]thieno[3,2-\u003cem\u003eb\u003c/em\u003e]carbazole, dibenzo[\u003cem\u003eb\u003c/em\u003e,\u003cem\u003ed\u003c/em\u003e]thiophen-1-ylboronic acid, 1-bromo-2-nitrobenzene and 12\u003cem\u003eH\u003c/em\u003e-benzo[4,5]thieno[3,2-\u003cem\u003ea\u003c/em\u003e]carbazole, were obtained from Shanghai Bidepharm Technology Co., Ltd. or Shanghai Haohong Biomedical Technology Co., Ltd.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTheoretical calculations:\u0026nbsp;\u003c/strong\u003eSingle-molecule calculations were performed using Gaussian 16. Ground-state geometries and electronic structures were obtained at the B3LYP/6-311++G(d,p) level with Grimme\u0026rsquo;s D3 dispersion correction and Becke-Johnson damping. Harmonic frequency calculations confirmed that all optimized structures were true minima on the potential-energy surface, with no imaginary frequencies. All calculations were carried out in the gas phase. Molecular structures and orbitals were visualized using GaussView 6.0 and VMD 1.9.3,\u003csup\u003e51,52\u003c/sup\u003e and wavefunction analyses were performed with Multiwfn 3.8.\u003csup\u003e53\u003c/sup\u003e The geometry-dependent three-layer molecular-contact framework was constructed stepwise. An oxide substrate was first generated from the In\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (111) surface using a three-layer slab, after which the terminal phosphonic-acid group of each SAM was deprotonated to represent chemisorption on the oxide surface. A perovskite slab was then placed above the SAM layer to model interfacial defect passivation at the buried contact. Interfacial configuration sampling was accelerated using the MACE-MPA-0 machine-learning potential, and the lowest-energy structure was used for first-principles optimization. First-principles calculations were performed using CP2K within the PBE generalized-gradient approximation with DFT-D3(BJ) dispersion correction, using the GPW scheme with the DZVP-MOLOPT-SR-GTH basis set and corresponding GTH pseudopotentials. The bottom ITO layer and the topmost perovskite atomic layer were fixed during structural relaxation to mimic substrate and bulk constraints.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePerovskite film and device fabrication:\u0026nbsp;\u003c/strong\u003ePSCs were fabricated with the architecture ITO/SAMs/Cs\u003csub\u003e0.005\u003c/sub\u003eFA\u003csub\u003e0.995\u003c/sub\u003ePbI\u003csub\u003e3\u003c/sub\u003e/C\u003csub\u003e60\u003c/sub\u003e/BCP/Ag. Cleaned ITO glass substrates were treated with UV-ozone for 15 min. Different SAM solutions in IPA (1 mg mL\u003csup\u003e-1\u003c/sup\u003e) were then spin-coated onto the substrates at 3,000 rpm for 30 s, followed by annealing at 100 \u0026deg;C for 10 min. The perovskite layer was deposited by a one-step spin-coating process. CsI (2.49 mg), PbI\u003csub\u003e2\u003c/sub\u003e (933.42 mg), FAI (322.85 mg) and MACl (31.73 mg) were dissolved in 1 mL of mixed solvent containing DMSO (200 \u0026mu;L) and DMF (800 \u0026mu;L), and the solution was stirred at 25 \u0026deg;C for 8 h. After filtration, the precursor solution was spin-coated onto the SAM-modified substrates at 6,000 rpm for 60 s, during which 220 \u0026mu;L of chlorobenzene was dropped onto the spinning substrate in the final 15 s. The films were then annealed at 110 \u0026deg;C for 20 min. Subsequently, a PDADI solution in IPA (1 mg mL\u003csup\u003e-1\u003c/sup\u003e) was spin-coated onto the perovskite films at 3,000 rpm for 30 s, followed by annealing at 100 \u0026deg;C for 10 min. The samples were then transferred to a thermal evaporator for sequential deposition of C\u003csub\u003e60\u003c/sub\u003e (25 nm), BCP (5 nm) and Ag (100 nm). Finally, an MgF\u003csub\u003e2\u003c/sub\u003e anti-reflection layer with a thickness of approximately 120 nm was deposited on the glass side by thermal evaporation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSolar cell characterization:\u0026nbsp;\u003c/strong\u003eCurrent density-voltage (𝐽-𝑉) characteristics were measured at room temperature in a nitrogen-filled glovebox using a Keithley 2410 source meter under simulated AM 1.5G illumination from a xenon arc lamp. The light intensity was calibrated before measurement using a Sciencetech SCI-REF-Q silicon reference cell. No preconditioning was applied, and the scan time was 10 s. The active area of the devices was defined by an opaque metal mask with an aperture area of 0.058 cm\u003csup\u003e2\u003c/sup\u003e or 1.004 cm\u003csup\u003e2\u003c/sup\u003e. External quantum efficiency (EQE) measurements were performed without applied bias in ambient air using an MNPVQE300 Quantum Efficiency Measurement System (Millennial Solar). Bias illumination was provided by bright LEDs with emission peaks at 900 nm and 400 nm.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStability tests of solar cells:\u0026nbsp;\u003c/strong\u003eFor thermal and humidity stability measurements, devices were stored under damp-heat conditions at 85 \u0026deg;C and 85% relative humidity, and \u003cem\u003eJ\u003c/em\u003e-V curves were recorded periodically. For long-term maximum power point tracking (MPPT), devices were measured under an LED-based solar simulator calibrated to approximately 1 sun with a standard silicon reference cell. Samples were placed in a tightly sealed chamber under continuous N\u003csub\u003e2\u003c/sub\u003e flow. During operation, the device temperature was maintained at approximately 65 \u0026deg;C and monitored by an internal sensor. The steady-state power output was tracked at a constant bias of 1000 mV using a system supplied by Wuhan 91PVK Solar Technology, while \u003cem\u003eJ\u003c/em\u003e-V curves were recorded periodically throughout the test.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eOther characterizations:\u0026nbsp;\u003c/strong\u003eUV-vis absorption spectra were recorded on a \u003cstrong\u003eShimadzu UV-2700\u003c/strong\u003e spectrophotometer using solutions (\u003cstrong\u003e1 \u0026times; 10\u003c/strong\u003e\u003csup\u003e-5\u003c/sup\u003e \u003cstrong\u003eM\u003c/strong\u003e) at room temperature. PL spectra were measured on a \u003cstrong\u003eHitachi F-7100\u003c/strong\u003e fluorescence spectrophotometer at \u003cstrong\u003e298 K\u003c/strong\u003e. PL mapping was performed on a \u003cstrong\u003ePicoQuant MicroTime 100/FluoTime 100\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003esystem using a \u003cstrong\u003e405 nm\u003c/strong\u003e pulsed diode laser (\u003cstrong\u003ePDL 828 \u0026lsquo;Sepia II\u0026rsquo;\u003c/strong\u003e). TRPL decay curves were collected on a \u003cstrong\u003eFluoTime 300\u003c/strong\u003e system (PicoQuant GmbH) with a \u003cstrong\u003e375 nm\u003c/strong\u003e picosecond pulsed diode laser. fs-TA spectroscopy was performed using a \u003cstrong\u003efrequency-doubled mode-locked Ti:sapphire femtosecond laser\u003c/strong\u003e (Coherent) coupled to an \u003cstrong\u003eoptical parametric amplifier\u003c/strong\u003e. The \u003cstrong\u003e35 fs, 1 kHz\u003c/strong\u003e output was split to generate \u003cstrong\u003e600 nm\u003c/strong\u003e pump pulses and a \u003cstrong\u003ewhite-light continuum probe (320-650 nm)\u003c/strong\u003e; the pump fluence was \u003cstrong\u003e1 \u0026mu;J cm\u003c/strong\u003e\u003csup\u003e-2\u003c/sup\u003e per pulse. Absolute PL quantum yields of perovskite films were measured on a \u003cstrong\u003eHamamatsu C13534\u003c/strong\u003e UV-NIR spectrometer equipped with an integrating sphere under dry Ar, using \u003cstrong\u003e320 nm\u003c/strong\u003e excitation. FTIR spectra were recorded on a \u003cstrong\u003eNicolet 6700\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003espectrometer. CV measurements were carried out on a \u003cstrong\u003eCHI600\u003c/strong\u003e electrochemical workstation at \u003cstrong\u003e100 mV s\u003c/strong\u003e\u003csup\u003e-1\u003c/sup\u003e using a three-electrode configuration with a glassy carbon working electrode, a Pt wire counter electrode and an Ag/AgCl reference electrode. UPS and XPS measurements were performed on a \u003cstrong\u003eThermo Scientific ESCALAB 250Xi\u003c/strong\u003e system using \u003cstrong\u003eHe I radiation (21.22 eV)\u003c/strong\u003e and \u003cstrong\u003emonochromated Al K\u003c/strong\u003e\u0026alpha; \u003cstrong\u003eradiation (1486.6 eV)\u003c/strong\u003e, respectively. GIWAXS measurements were performed at the \u003cstrong\u003eBL14B1\u003c/strong\u003e beamline of the \u003cstrong\u003eShanghai Synchrotron Radiation Facility\u003c/strong\u003e using an X-ray wavelength of \u003cstrong\u003e0.12398 nm\u003c/strong\u003e. AFM measurements were conducted on a \u003cstrong\u003eDimension FastScan\u003c/strong\u003e system (Bruker). KPFM images were acquired on an \u003cstrong\u003eAsylum Cypher S\u003c/strong\u003e microscope (Oxford Instruments) using a \u003cstrong\u003eTi\u0026ndash;Ir-coated ASYELEC.01-R2 cantilever\u003c/strong\u003e (\u003cem\u003ek\u003c/em\u003e = 4 \u0026plusmn; 0.5 N m\u003csup\u003e-1\u003c/sup\u003e). SEM images were obtained on a \u003cstrong\u003eZeiss Sigma 300\u003c/strong\u003e field-emission microscope equipped with an \u003cstrong\u003eOxford Xplore 30\u003c/strong\u003e energy-dispersive X-ray spectrometer, operating in secondary-electron mode at \u003cstrong\u003e3 kV\u003c/strong\u003e after Au sputter-coating.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e51. M. J. Frisch, G. W. T., H. B. Schlegel, G. E. Scuseria, \u003cem\u003e\u0026nbsp;et al.\u003c/em\u003e \u003cem\u003eGaussian 16, Revision A.03\u003c/em\u003e (Gaussian, Inc.: Wallingford CT, 2016).\u003c/p\u003e\n\u003cp\u003e52. Liu, Z.\u003cem\u003e\u0026nbsp;et al.\u003c/em\u003e An sp-hybridized all-carboatomic ring, cyclo[18]carbon: Electronic structure, electronic spectrum, and optical nonlinearity. \u003cem\u003eCarbon\u003c/em\u003e \u003cstrong\u003e165\u003c/strong\u003e, 461-467 (2020).\u003c/p\u003e\n\u003cp\u003e53. Lu, T. \u0026amp; Chen, F. Multiwfn: A multifunctional wavefunction analyzer. \u003cem\u003eJ. Comput. Chem.\u003c/em\u003e \u003cstrong\u003e33\u003c/strong\u003e, 580-592 (2012).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"inverted perovskite solar cells, self-assembled monolayer, power-conversion efficiency, interfacial engineering, frontier-orbital coupling","lastPublishedDoi":"10.21203/rs.3.rs-9432790/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9432790/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Record efficiencies in inverted perovskite solar cells (PSCs) are increasingly depend on precise energetic and electronic matching of self-assembled monolayers (SAMs) at buried interfaces(1-6). Yet most SAM designs address only one dimension of interfacial control, emphasizing either defect passivation at the perovskite contact or work-function alignment at the electrode (7-10). Moreover, hopping-mediated charge transport across the functional monolayer is often overlooked (11-13). Here we establish a geometry-dependent three-layer molecular-contact framework by integrating a multiple-site fixation strategy with fusion-topology reconfiguration of a benzothienocarbazole scaffold, enabling bidirectional anchoring and geometry-tailored frontier-orbital coupling across both interfaces. The resulting interfacial synergy suppresses defect formation, facilitates charge extraction, and therefore delivers a record high power conversion efficiency (PCE) of 28.11% (27.78% certified) in inverted PSCs, while retaining over 95% of the initial efficiency after 1,500 hours aging according to ISOS-L-2 protocol. This work defines a transport-aware, dual-interface-anchored SAM design model that enables the synergistic optimization of interfacial energetics, defect passivation and charge-transfer kinetics within a unified molecular framework.","manuscriptTitle":"Geometry-dependent monolayers for efficient inverted perovskite solar cells","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-07 08:24:02","doi":"10.21203/rs.3.rs-9432790/v1","editorialEvents":[],"status":"published","journal":{"display":false,"email":"[email protected]","identity":"nature","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"nature","sideBox":"Learn more about [Nature](http://www.nature.com/nature/)","snPcode":"","submissionUrl":"","title":"Nature","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"c1ae88ba-9c8f-4f25-a20e-2e8c0029ec7f","owner":[],"postedDate":"May 7th, 2026","published":true,"recentEditorialEvents":[{"type":"reviewerAgreed","content":"This content is not available.","date":"2026-05-06T16:00:02+00:00","index":3,"fulltext":"This content is not available."},{"type":"reviewerAgreed","content":"This content is not available.","date":"2026-05-06T03:16:01+00:00","index":2,"fulltext":"This content is not available."},{"type":"reviewerAgreed","content":"This content is not available.","date":"2026-05-06T02:56:12+00:00","index":1,"fulltext":"This content is not available."},{"type":"reviewersInvited","content":"3","date":"2026-05-05T17:46:16+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":67581566,"name":"Physical sciences/Energy science and technology/Energy harvesting"},{"id":67581567,"name":"Physical sciences/Materials science/Materials for devices"}],"tags":[],"updatedAt":"2026-05-07T08:24:02+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-07 08:24:02","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9432790","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9432790","identity":"rs-9432790","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}