Enabling over 20% Efficiency Organic Solar Cells by Molecular Configuration Modulation of Naphthalene Diimide-based Cathode Interlayers

Enabling over 20% Efficiency Organic Solar Cells by Molecular Configuration Modulation of Naphthalene Diimide-based Cathode Interlayers | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 6 February 2026 V1 Latest version Share on Enabling over 20% Efficiency Organic Solar Cells by Molecular Configuration Modulation of Naphthalene Diimide-based Cathode Interlayers Authors : Yixun Shu , Qihang Liu , Yetai Cheng , Yonghuan Li , Tong Sun , Xing Yan , Luyao Yang 0009-0009-4953-594X , … Show All … , Yawen Guo , Andong Zhang 0009-0002-3629-1252 , Xiangwei Zhu , Huanxiang Jiang , Qinye Bao , Yifan Wang , Xiaodong Wang , Zhishan' Bo , and Yahui Liu 0000-0002-3572-2308 [email protected] Show Fewer Authors Info & Affiliations https://doi.org/10.22541/au.177036159.98553810/v1 Published ACS Applied Materials & Interfaces Version of record Peer review timeline 144 views 46 downloads Contents Abstract Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Cathode interlayers (CILs) are pivotal to achieving high power conversion efficiency (PCE) in organic solar cells (OSCs). Herein, three D-A type CILs (NDIT1, NDI1, NDIT2) with different bridging structures were designed and synthesized through molecular configuration regulation. We then conducted a systematic investigation to unravel the influence of these distinct molecular structures on OSCs performance. In this series, the rigid fused ring bridge in NDIT2 endows a significantly improved planar molecular skeleton, which not only promotes enhanced intrinsic crystallinity but also leads to a significantly stronger self-doping effect. Moreover, this optimized configuration enables NDIT2 to exhibit highly ordered molecular assembly, which directly facilitates the formation of a uniform, low-defect nanostructure at the interface with the photoactive layer, which facilitates charge transport and extraction efficiency while effectively suppressing charge recombination losses. As a result, OSCs based on NDIT2 deliver a champion PCE of 20.03%, exceeding the efficiency of 18.95% for devices based on NDIT1 and 19.16% for devices based on NDI1along with excellent initial operational stability. This study provides an effective and rational strategy for designing high-performance cathodes by precisely optimizing the performance of CILs through targeted molecular structure regulation. 1 Introduction Organic solar cells (OSCs) have attracted extensive research interest over the past decades, primarily driven by their compelling advantages such as lightweight, flexibility, and solution processability [1-6] . Recent advances in non‑fullerene acceptors (NFAs) and device engineering have collectively pushed the power conversion efficiency (PCE) of single‑junction OSCs beyond the significant milestone 20% [7-10] . In this progress, the role of Cathode interlayers (CILs) has evolved substantially, transforming from a component that merely ensures ohmic contact into a crucial element that actively regulates interfacial energy level alignment, dictates charge extraction kinetics, and significantly influences overall device stability. Therefore, an ideal CIL must fulfill multiple requirements: efficient modification of the electrode work function, high intrinsic charge transport capability, and excellent compatibility with the active layer. Polymer CILs (such as PFN-Br, PNDIT-F3N) have demonstrated great utility but often limited by batch variations and limited thickness tolerance, hindering their reproducible and large‑scale application [11-13] . In contrast, small molecule CILs have emerged as a prominent research focus due to their unique advantages [14] . These advantages are primarily attributed to the define and simple molecular structure, which not only ensures high repeatability of material preparation and modification effects, but also demonstrates significant advantages in cost control and mass production. For example, small molecules based on PDI or NDI cores and modified with amino groups or other polar terminal groups, such as PDINO and PDINN, have been successfully used as CILs to push device PCE to over 19% [15-18] . However, a persistent challenge with these materials is that the large and planar conjugated skeletons of the core units often induce excessive and undesirable aggregation. This aggregation tendency adversely affects their film formation and typically leads to unsatisfactory interfacial contact with the active layer. To further optimize performance and effectively address these issues, the donor-acceptor-donor (D-A-D) and donor-acceptor (D-A) type CILs (such as SME1) are widely adopted [19, 20] . This design strategy facilitates stronger intramolecular charge transfer and self-doping effects, and allows for flexible and precise adjustment of frontier orbital energy levels by judicious selection and modification of the donor units. The relationship between the molecular structure and performance of CILs is complex and multilevel, primarily encompassing: the molecular structure firstly determines its configuration and planarity, which in turn governs the molecular packing behavior in the solid state, the degree of intramolecular charge delocalization, and simultaneously influences the molecular self-doping characteristics. These derived material characteristics affect the crystalline properties and interfacial morphology of the material, further influencing the charge extraction and recombination kinetics of the device, ultimately determining its photovoltaic performance [21-23] . By systematically modifying the configuration of the bridging unit, molecular planarity, packing order, self-doping intensity, and crystallization behavior can be actively controlled. Herein, three molecules were designed using NDI as the core while maintaining identical strong polar dimethylamino-fluorene terminals, varying only the core-terminal connectivity. This yields the benchmark molecule NDI1 (direct linkage), NDIT1 (single-bonded thiophene bridge), and NDIT2 (rigid, planar fused thiophene-NDI unit). This series enables a precise focus on molecular configuration change to systematically elucidate the complete transduction mechanism from molecular design to device function. Systematic analysis reveals that NDIT2, featuring a fused bridging unit, exhibits pronounced integrated advantages across all levels: an improved planar molecular skeleton, enhanced crystallinity, a markedly boosted self-doping effect, an optimized interfacial morphology, and highly efficient charge dynamics. These combined attributes contribute synergistically to the achievement of a high PCE of 20.03% in binary OSCs based on the D18:L8-BO active layer, with a notably high FF and J sc, exceeding the efficiency of 18.95% for NDIT1-based devices and 19.17% for NDI1-based devices. This PCE ranks among the highest reported for binary devices, and the corresponding devices also show promising initial operational stability. The study confirms that molecular configuration modulation serves as an effective molecular strategy for advancing CIL interfacial properties, offering a new design perspective for next‑generation interlayer materials. 2 Results and Discussion In this study, three donor-acceptor (D-A) type CILs were designed and synthesized, with their molecular structures shown in Figure 1a (see Scheme S1 in the Supporting Information for synthetic details). This molecular series employs naphthalene diimide (NDI) or its fused-ring derivative as the electron-deficient unit (A) and dimethylamine-functionalized fluorenes as the electron-donating terminal unit (D). Specifically, NDI1 incorporates an NDI core directly linked to the fluorene unit, creating a structure prone to steric hindrance. By introducing a thiophene bridging unit based on NDI, NDIT1 was synthesized. To further enhance rigidity and planarity, the NDI unit was fused with thiophene to construct a naphthodithiophene diimide (NDIT) core, resulting in the target molecule NDIT2. All molecules were efficiently prepared via palladium-catalyzed Suzuki coupling reactions with high yields. Their chemical structures were confirmed by ¹H NMR spectroscopy (Figures S1-S3). Benefiting from their well-defined small molecular structures, the three CILs exhibit high repeatability of material preparation and potential for large-scale production. Furthermore, the side chains on the central NDI and fluorene units endow these molecules with good solubility in various common organic solvents, such as chloroform, Dichloromethane, methanol, ethanol, and tetrahydrofuran, providing multiple options for device processing. Figure 1. a) Synthetic routes for NDIT1, NDI1, and NDIT2. b) Molecular structures of D18 and L8-BO. c) Molecular configurations and d) electrostatic potential distributions for NDIT1, NDI1, and NDIT2 by DFT. First, the influence of the distinct molecular structures on their fundamental photophysical properties was investigated using UV-Vis absorption spectroscopy in both methanol solution and thin film states, as shown in Figure 2a and Figure S4. All materials show characteristic absorptions consisting of two primary bands: a 300–400 nm band from π-π* transitions and a 400–700 nm band from the Intramolecular charge transfer (ICT) from the terminal donor to the core acceptor. NDIT2 exhibits the strongest ICT absorption, indicating its strongest intramolecular electron-pushing and electron-pulling effects and highest degree of charge separation [24-26] . This enhanced ICT characteristic is directly linked to its superior molecular configuration and electrostatic potential changes, which contribute to the formation of a more pronounced self-doping effect, as will be detailed in the subsequent analysis. The electrochemical properties of the CILs were characterized by cyclic voltammetry (CV) to determine their frontier orbital energy levels (Figure 3b). As shown in Figure S6, during the oxidation and reduction processes, by utilizing the empirical formulas E HOMO/LUMO =−e [ E ox/red + 4.80 − E (Fc/Fc + ) ], we calculated the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels of CILs [27, 28] . For NDI1, NDIT1, and NDIT2, HOMO levels are -5.89, -5.53, and -5.63 eV; LUMO levels are -4.12, -4.00, and -4.07 eV, yielding electrochemical bandgaps of 1.77, 1.53, and 1.56 eV, respectively. The low LUMO levels (~-4.0 eV) confirm n-type semiconductor character, beneficial for electron transport and hole blocking, meeting CIL requirements. The ability of the CILs to lower the electron extraction barrier (via modification of the metal electrode’s work function) was investigated using ultraviolet photoelectron spectroscopy (UPS).We measured UPS spectra for thin films of NDI1, NDIT1, and NDIT2 on Ag substrates and pure Ag (Figure 2b). The work function, derived from the secondary electron cutoff (SEC), shifted from 4.81 eV (bare Ag) to 4.03 eV, 4.44 eV, and 4.42 eV after deposition of NDI1, NDIT1, and NDIT2, respectively (ΔΦ = -0.78, -0.37, -0.39 eV; Table S5). This confirms the formation of effective interfacial dipoles by all materials, achieving the work function reduction necessary for forming an ohmic contact between the active layer and the Ag cathode. NDI1 demonstrated the most potent modulation, with NDIT1 and NDIT2 showing similar, and moderate efficacy [29, 30] . Density functional theory (DFT) calculations were performed at the PBE1PBE/6-311G(d) level to investigate the ground-state geometry, frontier molecular orbitals, and electrostatic potential (ESP) distribution (Figure 1c 1d, Figure S4). The calculations reveal significant differences in backbone planarity among the three CILs. For NDI1, direct linkage between the NDI core and the fluorene results in a large dihedral angle of 60° between the core and terminal units, leading to a twisted conformation. For NDIT1, the introduction of a thiophene bridge reduces the relevant dihedral angles to 48° (between NDI and thiophene) and 29° (between thiophene and fluorene). however, a significant molecular twist persists. In contrast, NDIT2 exhibits the smallest dihedral angle of only 23°between the NDIT core and the fluorene unit, demonstrating optimal planarity [31, 32] . As shown in Figure S4, frontier molecular orbital analysis indicates that LUMOs of all the three molecules are localized on the NDI/NDIT core. Notably, NDIT2 displays more uniform electron cloud delocalization across its fused NDIT core in the LUMO, laying a favorable electronic structure foundation for efficient electron transport. Furthermore, ESP analysis (Figure 1d) shows that NDIT2 possesses the most pronounced intramolecular charge separation, suggesting its potential for stronger interfacial interactions [33] . Figure 2. a) Normalized UV-Vis absorption spectrum of NDIT1, NDI1, and NDIT2 in methanol. b) UPS spectra of Ag electrode treated with NDIT1, NDI1and NDIT2, c) XRD patterns. d) EPR spectra of the powder samples of NDIT1, NDI1, and NDIT2. To elucidate how these molecular-level differences translate into distinct solid-state aggregate structures, X-ray diffraction (XRD) characterization was performed. As shown in Figure 2c, their crystallization behaviors show marked differences. The XRD pattern of NDI1 exhibits no distinct diffraction peaks, indicating a predominantly amorphous aggregate structure. For NDIT1, only a weak diffraction peak appears in the low-angle region, suggesting a limited tendency for lamellar ordering. In stark contrast, NDIT2 displays ordered crystalline features, its pattern shows clear lamellar stacking signals at low angles and multiple sharp and intense diffraction peaks in the region corresponding to π-π stacking. These distinct structural features demonstrate that NDIT2 forms a highly ordered molecular packing with significantly higher crystallinity compared to NDIT1 and NDI1. In summary, the strong crystallinity demonstrated by NDIT2 contributes to the formation of a highly ordered morphology during interfacial assembly, ultimately facilitating efficient charge transport. To elucidate the influence of molecular structure on self-doping behavior, electron paramagnetic resonance (EPR) measurements were conducted on pure solid powders of CILs under equal-mass conditions. As shown in Figure 2d, their signal intensities differ markedly. NDIT2 exhibits the most pronounced EPR signal, confirming its strongest self-doping effect among the three. A clear but weak signal is observed for NDI1, while the signal for NDIT1 is minimal and barely detectable. This result aligns with the conclusions from photophysical characterization, validating that NDIT2 possesses enhanced ICT characteristics. This promotes spontaneous charge transfer and the self-doping process most effectively, which is conducive to efficient charge transport in OSCs [34, 35] . Figure 3. a) Device structure: Glass/ITO/2PACz/Active layer/CILs/Ag. b) Energy levels of CILs. c) J-V curves and d) EQE curves of NDIT1, NDI1, and NDIT2 based OSCs. e) Normalized PCE over storage time in N₂. Table 1 . Photovoltaic parameters of D18:L8-BO OSCs with different CILs under AM 1.5G, 100 mWcm⁻². NDIT1 0.913 26.45 25.23 a) 78.44 18.95(18.81±0.08) b) NDI1 0.914 26.69 25.37 a) 78.64 19.17(18.94±0.18) b) NDIT2 0.915 27.26 25.93 a) 80.33 20.03(19.87±0.12) b) a) Calculated J sc from the EQE spectra; b) The average PCE values and standard deviations from 10 individual devices. To evaluate the impact of the three CILs on device performance, conventional-structure OSCs were fabricated with the architecture: glass/ ITO/2PACz/active layer/CIL/Ag as illustrated in Figure 3a. The classic combination of D18 and L8-BO was selected as the polymer electron donor and small molecule electron acceptor, respectively [36] . Detailed fabrication and optimization procedures are provided in the Supporting Information. The J – V curves are shown in Figures 3c, with detailed photovoltaic parameters summarized in Table 1.The V oc values of devices based on NDIT1, NDI1, and NDIT2 are nearly identical, primarily because the work functions of Ag electrodes modified by all three CILs meet the basic requirement for forming ohmic contact. NDI1 shows moderate J sc and FF values of 26.69 mA cm⁻² and 78.64%, respectively. Notably, the device employed NDIT1 exhibits the lowest J sc and FF values in the three CILs (26.45 mA cm⁻² and 78.44%), whereas the device based on NDIT2 achieves the highest J sc values of 27.26 mA cm⁻² and an outstanding FF of 80.33%. Consequently, the corresponding PCEs are 18.95%, 19.17%, and 20.03% for NDIT1, NDI1, and NDIT2 based devices, respectively. This enhancement is mainly attributed to the synergistic optimization of J sc and FF. Such a comprehensive performance improvement points directly to fundamental differences in the microstructure and resultant electrical properties of NDIT2 compared to the other CILs. This PCE ranks among the highest reported for binary single-junction OSCs, even surpassing that of devices using the prevalent PDINN as the CIL, which typically yields a PCE around 19.48% with the same active layer [21]. Figures 3d presents the external quantum efficiency (EQE) spectra of the devices. The J sc values integrated from the EQE spectra ( J cal )deviate by less than 5% compared to the measured J sc , confirming the accuracy and reliability of the electrical characterization. Beyond initial optoelectronic performance, the preliminary storage stability of unencapsulated devices was tested under a nitrogen atmosphere, as shown in Figure 3e. All devices exhibited efficiency decay within the first 40 hours. Notably, the NDIT2 based device showed the slowest decay rate, with significantly higher efficiency retention than the NDI1 and NDIT1 based devices, suggesting that its interfacial structure contributes to enhanced device stability. Figure 4. a) J 1/2 –V characteristics of electron-only devices based on the D18:L8‑BO binary photoactive layer with different CILs. b) Dependence of V oc on the light intensity. c) Dependence of J sc on the light intensity. d) J-V curves under dark. e) J ph - V eff characteristics. f) PL spectra of D18 and D18/CILs bilayer films. To gain deeper insights into the differences in device performance parameters, particularly the superior J sc and FF of the device based on NDIT2 systematic investigations on charge transport and recombination dynamics were carried out for the devices based on NDI1, NDIT1, and NDIT2. First, to assess the capability of the interlayers to transport electrons, the electron mobility ( μ ₑ) was evaluated using the space-charge-limited-current (SCLC) method in electron-only devices [37] . As displayed in Fig. 4a, the μ ₑ values for NDIT1, NDI1, and NDIT2 are 2.64 × 10⁻⁴, 3.23 × 10⁻⁴, and 5.01 × 10⁻⁴ cm² V⁻¹ s⁻¹, respectively. Notably, devices based on NDIT2 yields the highest electron mobility in the OSCs, which is more conducive to balanced charge transport and serves as a primary reason for obtaining the high FF. Subsequently, to probe the charge recombination mechanisms, the dependence of both the J sc and V oc on the incident light intensity ( P light ) was investigated. The slope (n value) of V oc versus ln ( P light ) can reveal the extent of trap-assisted recombination, with an ideal value close to 1 kT/ q [38] . The measured results demonstrate that the device based on NDIT2 exhibits an n value of 1.02 kT/ q , which is closest to the ideal value compared to those devices based on NDI1 (1.06 kT/ q ) and NDIT1 (1.13 kT/ q ), confirming that trap-assisted recombination is significantly suppressed in the NDIT2-based device (Fig 4b), pointing to a lower density of defect states at its interface. Meanwhile, the relationship between J sc and P light can be described by J sc ∝ P light α , where an α value approaching 1 indicates weaker bimolecular recombination. As shown in Figure 4c, the device based in NDIT2 shows an α value of 0.997, which is higher than the values of 0.994 and 0.985 for the devices based on NDIT1 and NDI1, respectively. This indicates that bimolecular recombination is also effectively suppressed. The rectification properties and interface leakage of the devices were evaluated by analyzing the J–V characteristics under dark conditions [39] . As presented in Fig 4d, the device based on NDIT2 exhibits the smallest reverse saturation current density and the highest rectification ratio, indicating that leakage currents induced by interfacial defects are effectively suppressed. In addition, to decouple the processes of exciton dissociation and charge collection, we assessed the device performance by analyzing the photocurrent density ( J ph ) as a function of the effective applied voltage ( V eff ) Key parameters, including the saturation current density ( J sat ) and the maximum photocurrent density ( J max ), are summarized in Table S5. The exciton dissociation ( P diss ) and charge collection ( P coll ) can be calculated using the equations P diss = J ph / J sat and P coll = J max / J sat , respectively [40] . As shown in Fig 4e, the NDIT2‑based device achieves the highest P diss (97.97%) and P coll (91.27%), suggesting its optimal exciton dissociation and charge collection capabilities. The combination of excellent rectification characteristics and low leakage current collectively reflects the superior effectiveness of NDIT2 in modifying the electrode, optimizing energy‑level alignment, and reducing interfacial recombination. To gain direct insight into the interfacial exciton behavior and electron transfer efficiency under conditions relevant to device operation, we measured steady-state photoluminescence (PL) spectra of bilayer films consisting of the donor polymer D18 coated with the different CILs [41, 42] . As shown in Fig. 4f, the neat D18 film exhibits a strong intrinsic fluorescence peak at about 695 nm. After coating with a thin layer of any of the three CILs, the fluorescence emission from the underlying D18 layer is significantly quenched in intensity. Furthermore, the emission peak displays a noticeable red-shift. This observation confirms that efficient charge transfer occurs between D18 and the CILs, leading to the formation of specific interfacial charge-transfer states. Meanwhile, the photogenerated excitons can diffuse from the underlying D18 layer to the D18/CIL interface and be efficiently dissociated, with electrons subsequently extracted by the overlying CIL. Notably, the D18/NDIT2 bilayer film shows the highest fluorescence quenching efficiency (69%), indicating that NDIT2 possesses the optimal interfacial electron-extraction capability and efficient donor-exciton quenching ability [43] . Its unique molecular structure is more favorable for forming stable charge-transfer states at the interface, facilitating the charge separation process. Figure 5. a) AFM height images of D18:L8-BO films coated with different CILs. b) Contact angles of water/glycerol on D18:L8-BO and CIL-coated surfaces. To systematically elucidate the physical origins behind the interfacial behavior and performance differences among the three CIL materials (NDI1, NDIT1, and NDIT2), we first investigated their intrinsic thin-film properties, followed by a comprehensive study of their interfacial physicochemical characteristics and assembly morphology [44, 45] . The nanoscale morphological evolution and the resulting interfacial structure formed when the three CILs are spin-coated atop the D18:L8-BO active layer were systematically characterized using atomic force microscopy (AFM) in tapping mode, as shown in Fig. 5g. AFM results reveal distinctly different interfacial morphologies formed by the different CILs on the D18:L8-BO blend film. The film formed by D18:L8-BO/NDIT1 exhibits a moderate roughness ( R q = 1.25 nm) but is covered with uneven aggregates, displaying significant disorder and lack of a continuous, uniform structure. NDI1 forms an exceptionally smooth and uniform film ( R q = 0.49 nm) on the active layer surface. This is likely due to the weak crystallinity of NDI1, causing the molecules to lie flat on the surface. Most importantly, NDIT2 constructs a unique and highly ordered interfacial morphology on the active layer. AFM images clearly show that the D18:L8-BO/NDIT2 surface features uniformly distributed structures, forming a moderate roughness ( R q = 2.72 nm). Its moderate nanoscale roughness increases the effective contact area, while its high degree of order significantly reduces the probability of defect trapping during transport. Given the striking morphological differences, we characterized the surface energy (γ) via contact-angle measurements with water and glycerol (Fig. 5a–f, Table S2) to analyze the interfacial compatibility between the CILs and the active layer. The total surface energy (γ) of the three materials follows the order: NDIT2 > NDIT1 > NDI1 [31] . The highest surface energy endows NDIT2 with stronger interactions with the active layer. Concurrently, NDIT2 exhibits better planarity and crystallinity. These factors work synergistically to promote the formation of long-range, tightly packed self-assembly at the interface. In contrast, the weaker molecular crystallization and lower surface energy of NDIT1 and NDI1 are unfavorable for forming an ordered interfacial layer morphology, which is consistent with the AFM results above and explains the inferior performance of their corresponding photovoltaic devices. 3 Conclusion In summary, three CILs (NDIT1, NDI1, and NDIT2) were designed and synthesized through molecular configuration engineering. All three CILs exhibit good solubility, suitable energy levels, and effective electrode work function modification. Notably, the fused-ring bridge in NDIT2 confers a more planar configuration, enhanced intrinsic crystallinity, and stronger interfacial interactions, leading to the assembly of an ordered, low-defect nanoscale morphology on the active layer. This optimized interface, combined with a strong self-doping effect, enhances conductivity and electron transport. Consequently, devices with D18:L8-BO and based on NDIT2 achieved a PCE of 20.03%, an FF of 80.33%, and a J sc of 27.26 mA cm⁻², which significantly improved the PCE of devices based on NDIT1 by 18.95% and devices based on NDI1 by 19.16%. Furthermore, these devices demonstrated superior initial operational stability compared to the NDIT1 (18.95% PCE) and NDI1 (19.16% PCE). This work demonstrates that coordinated regulation of molecular crystallinity and interfacial self-assembly through molecular configuration modulation is an effective strategy for high-performance CILs, providing a clear molecular design guideline for efficient and stable OSCs. Supporting information The supporting information is available online at http://chem.scichina.com The supporting materials are published as submitted, without typesetting or editing. The responsibility for scientific accuracy and content remains entirely with the authors. Conflict of interest The authors declare no conflict of interest. Acknowledgement Financial support was received from the National Natural Science Foundation of China (Grant Nos. 22579096, 52433007), and the Taishan Scholars Program (Grant Nos. tstp20221121). Author Contributions Y. S., Q.L. and Y.C. contributed equally to this work References [1] Kini GP, Jeon SJ, Moon DK. 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Adv Mater , 2023 , 35(6): e2208211 Information & Authors Information Version history V1 Version 1 06 February 2026 Peer review timeline Published ACS Applied Materials & Interfaces Version of Record 11 Mar 2026 Published Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords cathode interlayers molecular configuration naphthodithiophene diimide organic solar cell self-doping Authors Affiliations Yixun Shu State Key Laboratory of Bio-Fibers and Eco-Textiles View all articles by this author Qihang Liu Qingdao University View all articles by this author Yetai Cheng State Key Laboratory of Bio-Fibers and Eco-Textiles View all articles by this author Yonghuan Li State Key Laboratory of Bio-Fibers and Eco-Textiles View all articles by this author Tong Sun State Key Laboratory of Bio-Fibers and Eco-Textiles View all articles by this author Xing Yan State Key Laboratory of Bio-Fibers and Eco-Textiles View all articles by this author Luyao Yang 0009-0009-4953-594X State Key Laboratory of Bio-Fibers and Eco-Textiles View all articles by this author Yawen Guo Beijing Normal University Beijing Key Laboratory of Energy Conversion and Storage Materials View all articles by this author Andong Zhang 0009-0002-3629-1252 State Key Laboratory of Bio-Fibers and Eco-Textiles View all articles by this author Xiangwei Zhu State Key Laboratory of Bio-Fibers and Eco-Textiles View all articles by this author Huanxiang Jiang State Key Laboratory of Bio-Fibers and Eco-Textiles View all articles by this author Qinye Bao East China Normal University View all articles by this author Yifan Wang Qingdao University View all articles by this author Xiaodong Wang State Key Laboratory of Bio-Fibers and Eco-Textiles View all articles by this author Zhishan' Bo State Key Laboratory of Bio-Fibers and Eco-Textiles View all articles by this author Yahui Liu 0000-0002-3572-2308 [email protected] State Key Laboratory of Bio-Fibers and Eco-Textiles View all articles by this author Metrics & Citations Metrics Article Usage 144 views 46 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Yixun Shu, Qihang Liu, Yetai Cheng, et al. Enabling over 20% Efficiency Organic Solar Cells by Molecular Configuration Modulation of Naphthalene Diimide-based Cathode Interlayers. Authorea . 06 February 2026. DOI: https://doi.org/10.22541/au.177036159.98553810/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . 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