Dual-Mechanism Synergistic Enhancement of Room-Temperature Phosphorescence in Carbazole Derivatives

Dual-Mechanism Synergistic Enhancement of Room-Temperature Phosphorescence in Carbazole Derivatives | 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 Research Article Dual-Mechanism Synergistic Enhancement of Room-Temperature Phosphorescence in Carbazole Derivatives Wangen Zhu, Chi Zhang, Delong Ma, Jiaying Yan, Yong Qi, Nuonuo Zhang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8602735/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 27 Mar, 2026 Read the published version in Journal of Fluorescence → Version 1 posted 8 You are reading this latest preprint version Abstract Small-molecule phosphorescent materials feature high chemical purity and tailorable luminescence, yet aggregation-caused quenching (ACQ) and poor thermal stability remain critical bottlenecks. Herein, we designed and synthesized a series of carbazole-based derivatives ( K-CN , K-Br₂ , K-Cl , K-Br ), These compounds have heavy - atom substituents (–Br, –Cl) and a rigid structure to enhance spin orbit coupling for efficient intersystem crossing. The rigid carbazole backbone suppresses non - radiative decay, and the optimized molecular structure avoids quenching. which exhibit relative extended phosphorescent afterglow durations (0.6-3 s), and long phosphorescence lifetimes ( τ p : 4.2-177.3 ms) at 77 K. Doping these compounds into a PMMA matrix yields composite materials with significantly enhanced room-temperature phosphorescence. K-CN stands out with the longest lifetime (177.3 ms) and room-temperature phosphorescent afterglow (2 s), and favorable energy level gaps (S₁–T₅ ≈ 0.158 eV) via TD-DFT calculations. which hold great potential for applications in optoelectronic devices such as organic light-emitting diodes (OLEDs). Phosphorescent Afterglow Phosphorescence Lifetime PMMA Doping Heavy atoms Rigid structure Figures Figure 1 Figure 2 Figure 3 Introduction Small-molecule phosphorescent materials typically existing as pure organic compounds or metal complexes [1–4] , offering distinct advantages, such as high purity, facile bandgap modulation, cost-effectiveness, excellent processability (e.g., solution-based film formation [5–8] ). Moreover, their emission color and lifetime can be precisely tuned via molecular engineering strategies [9–12] . Their phosphorescence emission originates from the radiative relaxation of excitons from the singlet state to the triplet state, a process inherently inefficient due to spin-forbidden nature [13–15] . However, these materials also suffer from notable drawbacks, such as ACQ [16] effects in the solid state, high volatility arising from poor thermal stability, and limited film uniformity constrained by their crystallization behavior [17–20] . For phosphorescent materials, improving phosphorescent quantum yield, extending afterglow duration, and regulating phosphorescent lifetime are crucial research objectives [21–23] . In terms of enhaceing the afterglow duration, and lifetime of phosphorescent materials, the key lies in stabilizing triplet excitons and suppressing non-radiative decay [24–26] . Core strategies include: introducing heavy atoms (e.g., Br, Cl) [27] to promote intersystem crossing (ISC) [28–29] ; constructing rigid microenvironments (e.g., doping polymers matrices [30] , forming hydrogen-bonding networks) to inhibit molecular vibration and rotation [31] ; optimizing molecular structure design and regulating π-π stacking distances to suppress ACQ [32] ; additionally, weakening the interaction between triplet excitons and oxygen and inhibiting their annihilation via approaches such as photocatalytic deoxygenation and inert atmosphere encapsulation [33–34] . In this work, we employed carbazole as the conjugated and rigid planar molecular backbone and synthesized a series of carbazole-based phosphorescent products with different substituents (-CN, -Br₂,-Cl, -Br) on carbazole ring in isolated yields of 68.5%–79% via one step. Introducing a strong electron-withdrawing group (formylpyrrole) into the carbazole core adopts twisted configurations to mitigate ACQ phenomenon [35–37] . Meanwhile, heavy atom can introduced to promote ISC, and thereby facilitate phosphorescent emission [38–39] . Results and Discussion As illustrated in Scheme 1 , K-CN , K-Br₂ , K-Cl and K-Br were prepared from four carbazole precursors bearing different substituents. All target compounds were obtained in a single step (experimental details are provided in the Supporting Information). After purification by column chromatography and recrystallization, their molecular structures were fully corroborated by ¹H/¹³C NMR spectroscopy and high-resolution mass spectrometry (HR-MS) (Figs.S1–S12). Single crystals of K-CN suitable for X-ray diffraction were grown by slow diffusion of n-hexane into its dichloromethane solution. As shown in Fig. 1 a, the crystal lattice exhibits an antiparallel π-stacked dimer motif with a centroid-to-centroid distance of 3.515 Å between adjacent phenyl rings, indicative of intermolecular π–π interactions (Table S1 ). Multiple non-covalent contacts are observed throughout the packing (Fig. 1 b), which rigidify the molecular conformation and effectively suppress non-radiative decay pathways associated with intramolecular motion. Table 1 phosphorescence data of K-CN , K-Br 2 , K-Cl and K-Br in solid-state K-CN K-Br 2 K-Cl K-Br RTP excitation wavelength (nm) 394 374 289 289 RTP emission wavelength (nm) 457, 560 559 482 479, 507 RTP lifetime (ms) 177.3 4.2 4.8 5.6 Table 1 shows that, among the investigated series, K-CN exhibits the longest room-temperature phosphorescence (RTP) lifetime of 177.3 ms (Fig. S13–S16). At 77 K it produces a green afterglow that persists for 3 s, with the phosphorescence maximum located at 394 nm (Fig. 2 a). K-Br₂ displays the second-most red-shifted emission peak at 374 nm; however, its RTP lifetime is the shortest (4.2 ms) and the yellow afterglow at 77 K lasts only 1.2 s. K-Cl and K-Br possess identical emission maxima at 289 nm, with RTP lifetimes of 4.8 ms and 5.6 ms, respectively. Their green afterglow durations at 77 K are 1.2 s for K-Cl and 1.5 s for K-Br . Thin films were prepared by dissolving each emitter in dichloromethane together with poly(methyl methacrylate) (PMMA) at a mass doping ratio of 10%. The solutions were cast onto clean glass plates, spread evenly and allowed to evaporate to dryness under ambient conditions. As shown in Fig. 2 b, all four doped films exhibit pronounced RTP. The 10 wt % K-CN @PMMA film displays a green afterglow that persists for 2 s, the longest duration among the series, whereas the remaining three materials show similar afterglow lifetimes of ~ 0.7 s. To gain deeper insight into the structure–phosphorescence property relationship, density functional theory (DFT) calculations were carried out [40] . All molecular structures were fully optimized at the B3LYP/6-311g (d,p) level. Subsequently, the energies of five singlet and triplet excited states were evaluated by means of TDDFT calculations in the same calculation level. Moreover, the spin-orbit coupling (SOC) values associated with transitions between individual orbitals were determined independently with the ORCA program [41] .The HOMOs and LUMOs are mainly delocalized on whole moleulars, and slightly charge transfer from carbazole backbone to formylpyrrole unit upon excitation with similar energy gap (4.5546 ~ 4.6292 eV). The energy gaps (ΔE Sn - Tn ) of K-CN and K-Br 2 are 0.1582(Fig. 3 a) and 0.0096 eV(Fig. 3 b), respectively, which fall into the region of efficient intersystem crossing (ISC) and thus favor the occurrence of the ISC process. For K-CN and K-Br , their ΔE Sn - Tn is around 0.41 eV(Fig. 3 d), locating in the moderate ISC region. Herein, ISC can take place but with a significantly reduced efficiency, which requires a strong spin-orbit coupling (SOC) to drive. From the analysis of SOC values, the SOC matrix element ζ(S 1 ,T 5 ) of K-CN (2.028 cm − 1 ) is relatively high than those other SOC pairs. In contrast, the ζ(S 1 ,T 5 ) of K-Br 2 (0.954 cm − 1 ) is the lowest among all the SOC pair. This theoretical finding is consistent with the experimental observation that the phosphorescent property of K-CN is superior to that of K-Br 2 . Conclusions In summary, this study successfully synthesized a series of small-molecule phosphorescent materials with different substituents (-CN, -Br₂,-Cl, -Br) via EDCI/DMAP-catalyzed condensation reaction using carbazole as the molecular backbone, achieving isolated yields of 68.5%–79%. The accuracy of their molecular structures and crystal configurations was confirmed by NMR, HRMS, and SCXRD. In terms of structural design, these compounds integrate multiple advantages: a large conjugated rigid plane, synergistic energy level regulation by the amide group and pyrrole ring, and enhanced SOC effect from heavy atom substituents and nitrogen-containing heteroatoms, laying a solid structural foundation for optimizing phosphorescent performance. SCXRD analysis revealed that compounds K-CN crystallize in the triclinic P-1 space group, where intermolecular weak C-H-π interactions and π-π stacking with distances of 3.515 Å construct a rigid microenvironment, effectively suppressing non-radiative decay. TD-DFT calculations demonstrated significant intramolecular electron cloud delocalization in their HOMO-LUMO orbitals, small S₁-Tₙ energy gaps (0.0096–0.4142 eV), and strong SOC effects (up to 3.086 cm⁻¹), which promote ISC and triplet exciton stabilization. Photophysical property tests showed that at low temperature (77 K), K-CN exhibits the longest afterglow (3 s), followed by K-Br₂ (2 s), K-Cl (1.5 s) and K-Br (1.5 s). After doping with PMMA. Among them, K-CN @PMMA-10% performed optimally, with an RTP lifetime of 177.3 ms and the longest room-temperature afterglow (2 s). This work provides a feasible approach for the design and development of high-performance small-molecule RTP materials, which hold great potential for applications in optoelectronic devices such as organic light-emitting diodes (OLEDs). Declarations Author Contributions Wangen Zhu original draft, Investigation. Yong Qi: Writing review & editing, Project administration, Funding acquisition, Conceptualization. Jiaying Yan: Writing review & editing. Chi Zhang: Resources, Investigation. Delong Ma: Resources, Investigation. Nuonuo Zhang: Writing review & editing, Supervision, Funding acquisition. Funding This work was supported by National Natural Science Foundation of China (No. 22378229), Hubei Provincial Natural Science Foundation of China (2024AFD158). Data Availability All data supporting the findings of this study are available within the paper and its Supplementary Information. Ethical Approval No biological studies involved in the manuscript hence any ethical clearance does not required. Consent to Participate Not applicable. Consent to Publish All the authors give their consent to publish the same work. Competing interests The authors declare no competing interests. References Chen Chengjian, Chi Zhenguo, Chong Kok Chan, et al. (2021). Carbazole isomers induce ultralong organic phosphorescence. Nature materials , 20(2), 175-180. https://doi.org/10.1038/s41563-020-0797-2 Wang T, De J, Wu S, et al. (2022). Thermally activated and aggregation‐regulated excitonic coupling enable emissive high‐lying triplet excitons. Angewandte Chemie International Edition , 61(33), e202206681. https://doi.org/10.1002/anie.202206681 Helen Williamson, James R MacCallum. (1993). Studies of the phosphorescence lifetime of carbazole in polymer matrices. European polymer journal , 29(2-3), 201-204. https://doi.org/10.1016/0014-3057(93)90083-R Upadhyay Manoj, Deka Raktim, Ray Debdas. Carbazole–Benzonitrile–Norbornadiene Conjugates for Photothermally Reversible Ambient Phosphorescence. The Journal of Physical Chemistry Letters , 15(11), 3191-3196. https://doi.org/10.1021/acs.jpclett.4c00495 Y Jiang Y, Sun Q, Yu H X. (2025). Recent progress on the carbazole-based small-molecule single-component organic room-temperature phosphorescence. Journal of Materials Chemistry C . https://doi.org/10.1039/D5TC03239C P A Teplyakov, V V Trusov. (1965). Phosphorescence spectra of acenaphthene, diphenyl, and carbazole. Soviet Physics Journal , 8(3), 47-50. https://doi.org/10.1007/BF00827916 Sivanarayanan Jibin, Vinod Kavya, Benoy Anitta, et al. (2025). Unlocking the Room Temperature Phosphorescence through Halogen Engineering in Carbazole Dimer. Chemistry – A European Journal , 31(31), e202500635. https://doi.org/10.1002/chem.202500635 Brannan Alexander C, Phuoc Nguyen Le, Linnolahti Mikko, et al. (2023). Organic persistent room temperature phosphorescence enabled by carbazole impurity. Frontiers in Chemistry , 10, 1008658. https://doi.org/10.3389/fchem.2022.1008658 A V Avdeev, M V Erina, O I Kulikova. (2006). Characteristic features of carbazole phosphorescence quenching by benzophenone molecules in toluene at 77 K. Journal of Applied Spectroscopy , 73(4), 624-626. https://doi.org/10.1007/s10812-006-0130-0 Chen Shuzhan, Liang Huayang, Zhang Yinfeng, et al. (2025). Halogen effect on phosphorescence of carbazole-based non-conventional organogels. Dyes and Pigments , 113296. https://doi.org/10.1016/j.dyepig.2025.113296 Zhang Yuefa, Sun Qikun, Chen Junwu, et al. (2022). Evoking ultra-long molecular room temperature phosphorescence of pure carbazole derivatives. Chemical Engineering Journal , 447, 137458. https://doi.org/10.1016/j.cej.2022.137458 Yuan Shou, Zhang Yuefa, Chen Junwu, et al. (2022). Effectively unlocking the potential molecular room temperature phosphorescence of pure carbazole derivatives. Advanced Optical Materials , 10(15), 2200090. https://doi.org/10.1002/adom.202200090 Díaz B C, Schulman S G, Carretero A S, et al. (2004). Facile Analysis Of Carbazole In Commercial Anthracene by Heavy Atom–Induced Room Temperature Phosphorescence. Polycyclic Aromatic Compounds , 24(1), 65-74. https://doi.org/10.1080/10406630490277452 Skrilec M, Love L J C. (1981). Micelle-stabilized room-temperature phosphorescence characteristics of carbazole and related derivatives. The Journal of Physical Chemistry , 85(14), 2047-2050. https://doi.org/10.1021/j150614a019 He Runying, Yang Yun, Zhou Qian, et al. (2024). Regulating room temperature phosphorescence of carbazole quaternization pyridine in polymer through Hofmeister effect. Aggregate , 5(6), e611. https://doi.org/10.1002/agt2.611 Qian Chen, Ma Zhimin, Fu Xiaohua, et al. (2022). More than carbazole derivatives activate room temperature ultralong organic phosphorescence of benzoindole derivatives. Advanced materials , 34(19), 2200544. https://doi.org/10.1002/adma.202200544 Morantz D J, Bilen C S. (1975). Thermoluminescence and induced phosphorescence in irradiated doped PMMA. Polymer , 16(10), 745-748. https://doi.org/10.1016/0032-3861(75)90192-5 Shi J, Tao W, Zhou Y, et al. (2024). Air-stable and ultralong room-temperature phosphorescence from doped poly (methyl methacrylate) for visual detection of volatile organic compounds. Chemical Engineering Journal , 498, 155737. https://doi.org/10.1016/j.cej.2024.155737 Knyazev A A, Krupin A S, Galyametdinov Y G. (2022). Luminescence behavior of PMMA films doped with Tb (III) and Eu (III) complexes. Journal of Luminescence , 242, 118609. https://doi.org/10.1016/j.jlumin.2021.118609 Zheng X, Jiang J, Lin Q, et al. (2023). Excitation-& concentration-dependent color-tunable ultra-long phosphorescence of isophthalonitriles doped polymers. Chemical Engineering Journal , 469, 143929. https://doi.org/10.1016/j.cej.2023.143929 Yue L, Sun Q, Zhang Y, et al. (2022). Organic phosphor doped thermoplastics with ultralong and memorable room temperature phosphorescence different from crystals. Chemical Engineering Journal , 433, 134307. https://doi.org/10.1016/j.cej.2021.134307 Zhu Y, Pan M, Ji W, et al. (2025). Modulating room-temperature phosphorescence of D-π-A luminogens via methyl substitution, positional isomerism, and host–guest doping. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy , 330, 125763. https://doi.org/10.1016/j.saa.2025.125763 Zhang Y, Liu J, Sun Q, et al. (2025). Significantly Enhanced Room Temperature Phosphorescence Afterglow via Dopant Isomerization and Doping Strategy. Dyes and Pigments , 113275. https://doi.org/10.1016/j.dyepig.2025.113275 Zang L, Shao W, Kwon M S, et al. (2020). Photoresponsive luminescence switching of metal‐free organic phosphors doped polymer matrices. Advanced Optical Materials , 8(23), 2000654. https://doi.org/10.1002/adom.202000654 Jiang J, Liu J, Hu C, et al. (2024). Construction and fine tuning of host-guest doping systems and the underlying mechanism of room temperature phosphorescence. Dyes and Pigments , 222, 111931. https://doi.org/10.1016/j.dyepig.2023.111931 Ma L, Sun S, Ding B, et al. (2021). Highly efficient room‐temperature phosphorescence based on single‐benzene structure molecules and photoactivated luminescence with afterglow. Advanced Functional Materials , 31(17), 2010659. https://doi.org/10.1002/adfm.202010659 Castex M C, Olivero C, Pichler G, et al. (2006). Fluorescence, room temperature phosphorescence and photodegradation of carbazole compounds in irradiated poly (methyl methacrylate) matrices. Synthetic metals , 156(9-10), 699-704. https://doi.org/10.1016/j.synthmet.2006.03.015 Velasco D S, De Moura A P, Medina A N, et al. (2010). Preparation, characterization, and spectroscopic properties of PC/PMMA doped blends: Study of the effect of rare-earth doping on luminescence, quenching rate, and lifetime enhancement. The Journal of Physical Chemistry B , 114(17), 5657-5660. https://doi.org/10.1021/jp911900r Chitnis D, Kalyani N T, Dhoble S J. (2019). Comprehensive study on photophysical properties of Eu (TTA) 3bipy phosphor molecularly doped in PMMA and PS matrices. Results in Physics , 13, 102302. https://doi.org/10.1016/j.rinp.2019.102302 Ding B, Ma X, Tian H. (2023). Recent advances of pure organic room temperature phosphorescence based on functional polymers. Accounts of Materials Research , 4(10), 827-838. https://doi.org/10.1021/accountsmr.3c00090 Li Y, Han S, Zhao H, et al. (2025). Efficient energy phosphorescence transfer and reversible phosphorescence in aromatic heterocyclic doped systems for advanced information storage. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy , 336, 126053. https://doi.org/10.1016/j.saa.2025.126053 Xiong S, Xiong Y, Wang D, et al. (2023). Achieving Tunable Organic Afterglow and UV‐Irradiation‐Responsive Ultralong Room‐Temperature Phosphorescence from Pyridine‐Substituted Triphenylamine Derivatives. Advanced Materials , 35(28), 2301874. https://doi.org/10.1002/adma.202301874 Gan N, Shi H, An Z, et al. (2018). Recent advances in polymer‐based metal‐free room‐temperature phosphorescent materials. Advanced Functional Materials , 28(51), 1802657. https://doi.org/10.1002/adfm.201802657 Yao W, Xiong H, Liao Q, et al. (2024). Promoting organic room temperature phosphorescence through in situ polymerization. Journal of Polymer Science , 62(2), 401-408. https://doi.org/10.1002/pol.20230442 Ţucureanu V, Romanițan C, Mihalache I, et al. (2025). PMMA-Au@ YAG: Ce phosphor deposited on flexible substrate for white light emitting devices. Materials Science and Engineering: B , 311, 117808. https://doi.org/10.1016/j.mseb.2024.117808 Guo J, Hu C, Liu J, et al. (2024). Mechanochromism, tunable pure organic room temperature phosphorescence, single-molecule near-white emission, digital encryption, and anti-counterfeiting. Dyes and Pigments , 221, 111760. https://doi.org/10.1016/j.dyepig.2023.111760 Liu H G, Lee Y I, Park S, et al. (2004). Photoluminescent behaviors of several kinds of europium ternary complexes doped in PMMA. Journal of luminescence , 110(1-2), 11-16. https://doi.org/10.1016/j.jlumin.2004.04.001 Zhou W, Wang M C, Zhao X. (2015). Poly (methyl methacrylate)(PMMA) doped with DCJTB for luminescent solar concentrator applications. Solar Energy , 115, 569-576. https://doi.org/10.1016/j.solener.2015.03.012 Jaffar B M, Swart H C, Ahmed H A A S, et al. (2019). Stability of Bi doped La2O3 powder phosphor and PMMA composites. Journal of Physics and Chemistry of Solids , 131, 156-163. https://doi.org/10.1016/j.jpcs.2019.04.004 M. J. Frisch, G. W.Trucks, H. B.Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, G. Scalmani, V. Barone, G. A. Petersson, H. Nakatsuji, X. Li, M. Caricato, A. V. Marenich, J. Bloino, B. G. Janesko, R. Gomperts, B. Mennucci, H. P. Hratchian, J. V. Ortiz, A. F. Izmaylov, J. L. Sonnenberg, Williams, F. Ding, F. Lipparini, F. Egidi, J. Goings, B. Peng, A. Petrone, T. Henderson, D. Ranasinghe, V. G. Zakrzewski, J. Gao, N. Rega, G. Zheng, W. Liang, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven, K. Throssell, Jr. J. A. Montgomery, J. E. Peralta, F. Ogliaro, M. J. Bearpark, J. J. Heyd, E. N. Brothers, K. N. Kudin, V. N. Staroverov, T. A. Keith, R. Kobayashi, J. Normand, K. Raghavachari, A. P. Rendell, J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, J. M. Millam, M. Klene, C. Adamo, R. Cammi, J. W. Ochterski, R. L. Martin, K. Morokuma, O. Farkas, J. B. Foresman, D. J. Fox, Gaussian 16, Revision C. 01, Gaussian, Inc., Wallingford CT, 2016. Neese, F. (2012). The ORCA program system. Wiley Interdisciplinary Reviews: Computational Molecular Science , 2(1), 73-78. https://doi.org/10.1002/wcms.81 Scheme Scheme 1 is available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files ManuscriptSI.docx Scheme1.docx Cite Share Download PDF Status: Published Journal Publication published 27 Mar, 2026 Read the published version in Journal of Fluorescence → Version 1 posted Editorial decision: Revision requested 03 Mar, 2026 Reviews received at journal 27 Feb, 2026 Reviewers agreed at journal 16 Feb, 2026 Reviewers agreed at journal 16 Feb, 2026 Reviewers invited by journal 11 Feb, 2026 Editor assigned by journal 05 Feb, 2026 Submission checks completed at journal 05 Feb, 2026 First submitted to journal 14 Jan, 2026 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-8602735","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":592407598,"identity":"103082ef-a45d-4cd9-b4fe-53a98ad63fc3","order_by":0,"name":"Wangen Zhu","email":"","orcid":"","institution":"China Three Gorges University","correspondingAuthor":false,"prefix":"","firstName":"Wangen","middleName":"","lastName":"Zhu","suffix":""},{"id":592407599,"identity":"69c256d9-7c2b-40c4-8141-26c0830eb86f","order_by":1,"name":"Chi Zhang","email":"","orcid":"","institution":"China Three Gorges University","correspondingAuthor":false,"prefix":"","firstName":"Chi","middleName":"","lastName":"Zhang","suffix":""},{"id":592407600,"identity":"9a9b3c77-4216-48fd-8486-eb77144bca47","order_by":2,"name":"Delong Ma","email":"","orcid":"","institution":"China Three Gorges University","correspondingAuthor":false,"prefix":"","firstName":"Delong","middleName":"","lastName":"Ma","suffix":""},{"id":592407601,"identity":"47a66be2-b218-4a51-8cba-7812edc51ece","order_by":3,"name":"Jiaying Yan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/ElEQVRIie3PMUvDQBjG8UcC1+U06xsU9SO8IdBaHPwqFzq4BOnYodQrgY66Ooj4ETp1vhJolkrWjI1dnUVQxCjOd3QTvP94vD8eDvD5/misAAl0ltuPER2HOxA5YLk+SyK9w1qX9mejdO4iXD6Z4WZcHPXCR0XRA+3NETTPtY2srxSrVSH7d43heEFBDyJJMhsxGbMSheTaKJUuSPS1FIdWUr205POHsFnek2TjInW7ks5aUul4OtVEThLV7Up6c9muyEGAFXGUO/5yUGXd+O31/IKrsnzHeHJ928mbrY2cGggGcoDU71NgOf/uRCPYABMgNI5Tn8/n+7d9AZP4UN5kllT2AAAAAElFTkSuQmCC","orcid":"","institution":"China Three Gorges University","correspondingAuthor":true,"prefix":"","firstName":"Jiaying","middleName":"","lastName":"Yan","suffix":""},{"id":592407607,"identity":"d2b60139-f4a0-4ff4-86db-b4eafeb51220","order_by":4,"name":"Yong Qi","email":"","orcid":"","institution":"China Three Gorges University","correspondingAuthor":false,"prefix":"","firstName":"Yong","middleName":"","lastName":"Qi","suffix":""},{"id":592407608,"identity":"89184b5d-58f2-434e-9782-a79c95267ac1","order_by":5,"name":"Nuonuo Zhang","email":"","orcid":"","institution":"China Three Gorges University","correspondingAuthor":false,"prefix":"","firstName":"Nuonuo","middleName":"","lastName":"Zhang","suffix":""}],"badges":[],"createdAt":"2026-01-14 14:23:31","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8602735/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8602735/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10895-026-04749-w","type":"published","date":"2026-03-27T16:13:24+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":102830960,"identity":"ea1e096b-6501-4f5a-ab23-f75b662022a4","added_by":"auto","created_at":"2026-02-17 09:56:49","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":165099,"visible":true,"origin":"","legend":"\u003cp\u003eUnit cells of (a) \u003cstrong\u003eK-CN\u003c/strong\u003e and intermolecular weak interactions of \u003cstrong\u003eK-CN\u003c/strong\u003e(b)\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8602735/v1/3e95a21fcc0e133e330f01d5.png"},{"id":102830953,"identity":"f465d6f2-5fa6-46ff-8ab2-bb3185b1c56b","added_by":"auto","created_at":"2026-02-17 09:56:45","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":94521,"visible":true,"origin":"","legend":"\u003cp\u003ePhosphorescent afterglow images of pristine compounds \u003cstrong\u003eK-CN\u003c/strong\u003e, \u003cstrong\u003eK-Br₂\u003c/strong\u003e, \u003cstrong\u003eK-Cl\u003c/strong\u003e, and \u003cstrong\u003eK-Br\u003c/strong\u003e at 77 K (a), RTP images of 10 wt% \u003cstrong\u003eK-CN\u003c/strong\u003e, \u003cstrong\u003eK-Br\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/sub\u003e, \u003cstrong\u003eK-Cl\u003c/strong\u003e, \u003cstrong\u003eK-Br\u003c/strong\u003e @PMMA with different doping ratios (b)\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8602735/v1/e384278977250bf56339a696.png"},{"id":102830955,"identity":"a383d771-b36e-4d34-bd72-8aec709f4b64","added_by":"auto","created_at":"2026-02-17 09:56:46","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":209566,"visible":true,"origin":"","legend":"\u003cp\u003eEnergy levels and spin-orbit coupling constants (ξ) and HOMO and LUMO distribution of (a) \u003cstrong\u003eK-CN\u003c/strong\u003e, (b) \u003cstrong\u003eK-Br\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e2\u003c/strong\u003e\u003c/sub\u003e, (c) \u003cstrong\u003eK-Cl\u003c/strong\u003e, (d) \u003cstrong\u003eK-Br\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8602735/v1/052d3b1047ebdaafa0c213e4.png"},{"id":105755059,"identity":"b5794a1d-d822-4baa-a4ab-dd7fb1d09c68","added_by":"auto","created_at":"2026-03-30 16:24:46","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":924804,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8602735/v1/1cb53f54-972f-4adb-8020-2849528f0c70.pdf"},{"id":102830958,"identity":"00a5d67b-c382-405d-b3ff-fbdac1c418a2","added_by":"auto","created_at":"2026-02-17 09:56:47","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":2619056,"visible":true,"origin":"","legend":"","description":"","filename":"ManuscriptSI.docx","url":"https://assets-eu.researchsquare.com/files/rs-8602735/v1/db2e6e4076b8c43de180497c.docx"},{"id":102962791,"identity":"e7089b7b-6760-479b-9e9d-b3faa68a6108","added_by":"auto","created_at":"2026-02-19 04:11:15","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":31266,"visible":true,"origin":"","legend":"","description":"","filename":"Scheme1.docx","url":"https://assets-eu.researchsquare.com/files/rs-8602735/v1/b2235db3613df8495a84afe8.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Dual-Mechanism Synergistic Enhancement of Room-Temperature Phosphorescence in Carbazole Derivatives","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSmall-molecule phosphorescent materials typically existing as pure organic compounds or metal complexes\u003csup\u003e[1\u0026ndash;4]\u003c/sup\u003e, offering distinct advantages, such as high purity, facile bandgap modulation, cost-effectiveness, excellent processability (e.g., solution-based film formation\u003csup\u003e[5\u0026ndash;8]\u003c/sup\u003e). Moreover, their emission color and lifetime can be precisely tuned via molecular engineering strategies\u003csup\u003e[9\u0026ndash;12]\u003c/sup\u003e. Their phosphorescence emission originates from the radiative relaxation of excitons from the singlet state to the triplet state, a process inherently inefficient due to spin-forbidden nature\u003csup\u003e[13\u0026ndash;15]\u003c/sup\u003e. However, these materials also suffer from notable drawbacks, such as ACQ\u003csup\u003e[16]\u003c/sup\u003eeffects in the solid state, high volatility arising from poor thermal stability, and limited film uniformity constrained by their crystallization behavior\u003csup\u003e[17\u0026ndash;20]\u003c/sup\u003e. For phosphorescent materials, improving phosphorescent quantum yield, extending afterglow duration, and regulating phosphorescent lifetime are crucial research objectives\u003csup\u003e[21\u0026ndash;23]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eIn terms of enhaceing the afterglow duration, and lifetime of phosphorescent materials, the key lies in stabilizing triplet excitons and suppressing non-radiative decay\u003csup\u003e[24\u0026ndash;26]\u003c/sup\u003e. Core strategies include: introducing heavy atoms (e.g., Br, Cl)\u003csup\u003e[27]\u003c/sup\u003e to promote intersystem crossing (ISC)\u003csup\u003e[28\u0026ndash;29]\u003c/sup\u003e; constructing rigid microenvironments (e.g., doping polymers matrices\u003csup\u003e[30]\u003c/sup\u003e, forming hydrogen-bonding networks) to inhibit molecular vibration and rotation\u003csup\u003e[31]\u003c/sup\u003e; optimizing molecular structure design and regulating π-π stacking distances to suppress ACQ \u003csup\u003e[32]\u003c/sup\u003e; additionally, weakening the interaction between triplet excitons and oxygen and inhibiting their annihilation via approaches such as photocatalytic deoxygenation and inert atmosphere encapsulation\u003csup\u003e[33\u0026ndash;34]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eIn this work, we employed carbazole as the conjugated and rigid planar molecular backbone and synthesized a series of carbazole-based phosphorescent products with different substituents (-CN, -Br₂,-Cl, -Br) on carbazole ring in isolated yields of 68.5%\u0026ndash;79% via one step. Introducing a strong electron-withdrawing group (formylpyrrole) into the carbazole core adopts twisted configurations to mitigate ACQ phenomenon\u003csup\u003e[35\u0026ndash;37]\u003c/sup\u003e. Meanwhile, heavy atom can introduced to promote ISC, and thereby facilitate phosphorescent emission\u003csup\u003e[38\u0026ndash;39]\u003c/sup\u003e.\u003c/p\u003e"},{"header":"Results and Discussion","content":"\u003cp\u003e \u003c/p\u003e \u003cp\u003eAs illustrated in Scheme \u003cspan refid=\"Sch1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, \u003cb\u003eK-CN\u003c/b\u003e, \u003cb\u003eK-Br₂\u003c/b\u003e, \u003cb\u003eK-Cl\u003c/b\u003e and \u003cb\u003eK-Br\u003c/b\u003e were prepared from four carbazole precursors bearing different substituents. All target compounds were obtained in a single step (experimental details are provided in the Supporting Information). After purification by column chromatography and recrystallization, their molecular structures were fully corroborated by \u0026sup1;H/\u0026sup1;\u0026sup3;C NMR spectroscopy and high-resolution mass spectrometry (HR-MS) (Figs.S1\u0026ndash;S12).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eSingle crystals of \u003cb\u003eK-CN\u003c/b\u003e suitable for X-ray diffraction were grown by slow diffusion of n-hexane into its dichloromethane solution. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea, the crystal lattice exhibits an antiparallel π-stacked dimer motif with a centroid-to-centroid distance of 3.515 \u0026Aring; between adjacent phenyl rings, indicative of intermolecular π\u0026ndash;π interactions (Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e). Multiple non-covalent contacts are observed throughout the packing (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb), which rigidify the molecular conformation and effectively suppress non-radiative decay pathways associated with intramolecular motion.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ephosphorescence data of \u003cb\u003eK-CN\u003c/b\u003e, \u003cb\u003eK-Br\u003c/b\u003e\u003csub\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sub\u003e, \u003cb\u003eK-Cl\u003c/b\u003e and \u003cb\u003eK-Br\u003c/b\u003e in solid-state\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eK-CN\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eK-Br\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eK-Cl\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eK-Br\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRTP excitation wavelength (nm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e394\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e374\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e289\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e289\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRTP emission wavelength (nm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e457, 560\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e559\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e482\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e479, 507\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRTP lifetime (ms)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e177.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows that, among the investigated series, \u003cb\u003eK-CN\u003c/b\u003e exhibits the longest room-temperature phosphorescence (RTP) lifetime of 177.3 ms (Fig. S13\u0026ndash;S16). At 77 K it produces a green afterglow that persists for 3 s, with the phosphorescence maximum located at 394 nm (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea). \u003cb\u003eK-Br₂\u003c/b\u003e displays the second-most red-shifted emission peak at 374 nm; however, its RTP lifetime is the shortest (4.2 ms) and the yellow afterglow at 77 K lasts only 1.2 s. \u003cb\u003eK-Cl\u003c/b\u003e and \u003cb\u003eK-Br\u003c/b\u003e possess identical emission maxima at 289 nm, with RTP lifetimes of 4.8 ms and 5.6 ms, respectively. Their green afterglow durations at 77 K are 1.2 s for \u003cb\u003eK-Cl\u003c/b\u003e and 1.5 s for \u003cb\u003eK-Br\u003c/b\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThin films were prepared by dissolving each emitter in dichloromethane together with poly(methyl methacrylate) (PMMA) at a mass doping ratio of 10%. The solutions were cast onto clean glass plates, spread evenly and allowed to evaporate to dryness under ambient conditions. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb, all four doped films exhibit pronounced RTP. The 10 wt % \u003cb\u003eK-CN\u003c/b\u003e@PMMA film displays a green afterglow that persists for 2 s, the longest duration among the series, whereas the remaining three materials show similar afterglow lifetimes of ~\u0026thinsp;0.7 s.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eTo gain deeper insight into the structure\u0026ndash;phosphorescence property relationship, density functional theory (DFT) calculations were carried out\u003csup\u003e[40]\u003c/sup\u003e. All molecular structures were fully optimized at the B3LYP/6-311g (d,p) level. Subsequently, the energies of five singlet and triplet excited states were evaluated by means of TDDFT calculations in the same calculation level. Moreover, the spin-orbit coupling (SOC) values associated with transitions between individual orbitals were determined independently with the ORCA program\u003csup\u003e[41]\u003c/sup\u003e.The HOMOs and LUMOs are mainly delocalized on whole moleulars, and slightly charge transfer from carbazole backbone to formylpyrrole unit upon excitation with similar energy gap (4.5546\u0026thinsp;~\u0026thinsp;4.6292 eV). The energy gaps (ΔE\u003csub\u003eSn\u003c/sub\u003e-\u003csub\u003eTn\u003c/sub\u003e) of \u003cb\u003eK-CN\u003c/b\u003e and \u003cb\u003eK-Br\u003c/b\u003e\u003csub\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sub\u003e are 0.1582(Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea) and 0.0096 eV(Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb), respectively, which fall into the region of efficient intersystem crossing (ISC) and thus favor the occurrence of the ISC process. For \u003cb\u003eK-CN\u003c/b\u003e and \u003cb\u003eK-Br\u003c/b\u003e, their ΔE\u003csub\u003eSn\u003c/sub\u003e-\u003csub\u003eTn\u003c/sub\u003e is around 0.41 eV(Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ed), locating in the moderate ISC region. Herein, ISC can take place but with a significantly reduced efficiency, which requires a strong spin-orbit coupling (SOC) to drive. From the analysis of SOC values, the SOC matrix element ζ(S\u003csub\u003e1\u003c/sub\u003e,T\u003csub\u003e5\u003c/sub\u003e) of \u003cb\u003eK-CN\u003c/b\u003e (2.028 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) is relatively high than those other SOC pairs. In contrast, the ζ(S\u003csub\u003e1\u003c/sub\u003e,T\u003csub\u003e5\u003c/sub\u003e) of \u003cb\u003eK-Br\u003c/b\u003e\u003csub\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sub\u003e (0.954 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e) is the lowest among all the SOC pair. This theoretical finding is consistent with the experimental observation that the phosphorescent property of \u003cb\u003eK-CN\u003c/b\u003e is superior to that of \u003cb\u003eK-Br\u003c/b\u003e\u003csub\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sub\u003e.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eIn summary, this study successfully synthesized a series of small-molecule phosphorescent materials with different substituents (-CN, -Br₂,-Cl, -Br) via EDCI/DMAP-catalyzed condensation reaction using carbazole as the molecular backbone, achieving isolated yields of 68.5%\u0026ndash;79%. The accuracy of their molecular structures and crystal configurations was confirmed by NMR, HRMS, and SCXRD. In terms of structural design, these compounds integrate multiple advantages: a large conjugated rigid plane, synergistic energy level regulation by the amide group and pyrrole ring, and enhanced SOC effect from heavy atom substituents and nitrogen-containing heteroatoms, laying a solid structural foundation for optimizing phosphorescent performance. SCXRD analysis revealed that compounds \u003cb\u003eK-CN\u003c/b\u003e crystallize in the triclinic P-1 space group, where intermolecular weak C-H-π interactions and π-π stacking with distances of 3.515 \u0026Aring; construct a rigid microenvironment, effectively suppressing non-radiative decay. TD-DFT calculations demonstrated significant intramolecular electron cloud delocalization in their HOMO-LUMO orbitals, small S₁-Tₙ energy gaps (0.0096\u0026ndash;0.4142 eV), and strong SOC effects (up to 3.086 cm⁻\u0026sup1;), which promote ISC and triplet exciton stabilization. Photophysical property tests showed that at low temperature (77 K), \u003cb\u003eK-CN\u003c/b\u003e exhibits the longest afterglow (3 s), followed by \u003cb\u003eK-Br₂\u003c/b\u003e (2 s), \u003cb\u003eK-Cl\u003c/b\u003e (1.5 s) and \u003cb\u003eK-Br\u003c/b\u003e (1.5 s). After doping with PMMA. Among them, \u003cb\u003eK-CN\u003c/b\u003e@PMMA-10% performed optimally, with an RTP lifetime of 177.3 ms and the longest room-temperature afterglow (2 s). This work provides a feasible approach for the design and development of high-performance small-molecule RTP materials, which hold great potential for applications in optoelectronic devices such as organic light-emitting diodes (OLEDs).\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e Wangen Zhu original draft, Investigation. Yong Qi: Writing review \u0026amp; editing, Project administration, Funding acquisition, Conceptualization. Jiaying Yan: Writing review \u0026amp; editing. Chi Zhang: Resources, Investigation. Delong Ma: Resources, Investigation. Nuonuo Zhang: Writing review \u0026amp; editing, Supervision, Funding acquisition.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e This work was supported by National Natural Science Foundation of China (No. 22378229), Hubei Provincial Natural Science Foundation of China (2024AFD158).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability\u003c/strong\u003e All data supporting the findings of this study are available within the paper and its Supplementary Information.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical Approval\u003c/strong\u003e No biological studies involved in the manuscript hence any ethical clearance does not required.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Participate\u0026nbsp;\u003c/strong\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Publish\u003c/strong\u003e All the authors give their consent to publish the same work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e The authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eChen Chengjian, Chi Zhenguo, Chong Kok Chan, et al. (2021). Carbazole isomers induce ultralong organic phosphorescence. \u003cem\u003eNature materials\u003c/em\u003e, 20(2), 175-180. https://doi.org/10.1038/s41563-020-0797-2\u003c/li\u003e\n \u003cli\u003eWang T, De J, Wu S, et al. (2022). Thermally activated and aggregation‐regulated excitonic coupling enable emissive high‐lying triplet excitons. \u003cem\u003eAngewandte Chemie International Edition\u003c/em\u003e, 61(33), e202206681. https://doi.org/10.1002/anie.202206681\u003c/li\u003e\n \u003cli\u003eHelen Williamson, James R MacCallum. (1993). Studies of the phosphorescence lifetime of carbazole in polymer matrices. \u003cem\u003eEuropean polymer journal\u003c/em\u003e, 29(2-3), 201-204. https://doi.org/10.1016/0014-3057(93)90083-R\u003c/li\u003e\n \u003cli\u003eUpadhyay Manoj, Deka Raktim, Ray Debdas. Carbazole\u0026ndash;Benzonitrile\u0026ndash;Norbornadiene Conjugates for Photothermally Reversible Ambient Phosphorescence. \u003cem\u003eThe Journal of Physical Chemistry Letters\u003c/em\u003e, 15(11), 3191-3196. https://doi.org/10.1021/acs.jpclett.4c00495\u003c/li\u003e\n \u003cli\u003eY\u0026nbsp;Jiang Y, Sun Q, Yu H X. (2025). Recent progress on the carbazole-based small-molecule single-component organic room-temperature phosphorescence. \u0026nbsp;\u003cem\u003eJournal of Materials Chemistry C\u003c/em\u003e. https://doi.org/10.1039/D5TC03239C\u003c/li\u003e\n \u003cli\u003eP A Teplyakov, V V Trusov. (1965). Phosphorescence spectra of acenaphthene, diphenyl, and carbazole. \u003cem\u003eSoviet Physics Journal\u003c/em\u003e, 8(3), 47-50. https://doi.org/10.1007/BF00827916\u003c/li\u003e\n \u003cli\u003eSivanarayanan Jibin, Vinod Kavya, Benoy Anitta, et al. (2025). Unlocking the Room Temperature Phosphorescence through Halogen Engineering in Carbazole Dimer. \u003cem\u003eChemistry\u003c/em\u003e\u003cem\u003e\u0026ndash;\u003c/em\u003e\u003cem\u003eA European Journal\u003c/em\u003e, 31(31), e202500635. https://doi.org/10.1002/chem.202500635\u003c/li\u003e\n \u003cli\u003eBrannan Alexander C, Phuoc Nguyen Le, Linnolahti Mikko, et al. (2023). Organic persistent room temperature phosphorescence enabled by carbazole impurity. \u003cem\u003eFrontiers in Chemistry\u003c/em\u003e, 10, 1008658. https://doi.org/10.3389/fchem.2022.1008658\u003c/li\u003e\n \u003cli\u003eA V Avdeev, M V Erina, O I Kulikova.\u0026nbsp;(2006). Characteristic features of carbazole phosphorescence quenching by benzophenone molecules in toluene at 77 K. \u003cem\u003eJournal of Applied Spectroscopy\u003c/em\u003e, 73(4), 624-626. https://doi.org/10.1007/s10812-006-0130-0\u003c/li\u003e\n \u003cli\u003eChen Shuzhan, Liang Huayang, Zhang Yinfeng, et al. (2025). Halogen effect on phosphorescence of carbazole-based non-conventional organogels. \u003cem\u003eDyes and Pigments\u003c/em\u003e, 113296. https://doi.org/10.1016/j.dyepig.2025.113296\u003c/li\u003e\n \u003cli\u003eZhang Yuefa, Sun Qikun, Chen Junwu, et al. (2022). Evoking ultra-long molecular room temperature phosphorescence of pure carbazole derivatives. \u003cem\u003eChemical Engineering Journal\u003c/em\u003e, 447, 137458. https://doi.org/10.1016/j.cej.2022.137458\u003c/li\u003e\n \u003cli\u003eYuan Shou, Zhang Yuefa, Chen Junwu, et al. (2022). Effectively unlocking the potential molecular room temperature phosphorescence of pure carbazole derivatives. \u003cem\u003eAdvanced Optical Materials\u003c/em\u003e, 10(15), 2200090. https://doi.org/10.1002/adom.202200090\u003c/li\u003e\n \u003cli\u003eD\u0026iacute;az B C, Schulman S G, Carretero A S, et al. (2004). Facile Analysis Of Carbazole In Commercial Anthracene by Heavy Atom\u0026ndash;Induced Room Temperature Phosphorescence. \u003cem\u003ePolycyclic Aromatic Compounds\u003c/em\u003e, 24(1), 65-74. https://doi.org/10.1080/10406630490277452\u003c/li\u003e\n \u003cli\u003eSkrilec M, Love L J C. (1981). Micelle-stabilized room-temperature phosphorescence characteristics of carbazole and related derivatives. \u003cem\u003eThe Journal of Physical Chemistry\u003c/em\u003e, 85(14), 2047-2050. https://doi.org/10.1021/j150614a019\u003c/li\u003e\n \u003cli\u003eHe Runying, Yang Yun, Zhou Qian, et al. (2024). Regulating room temperature phosphorescence of carbazole quaternization pyridine in polymer through Hofmeister effect. \u003cem\u003eAggregate\u003c/em\u003e, 5(6), e611. https://doi.org/10.1002/agt2.611\u003c/li\u003e\n \u003cli\u003eQian Chen, Ma Zhimin, Fu Xiaohua, et al. (2022). More than carbazole derivatives activate room temperature ultralong organic phosphorescence of benzoindole derivatives. \u003cem\u003eAdvanced materials\u003c/em\u003e, 34(19), 2200544. https://doi.org/10.1002/adma.202200544\u003c/li\u003e\n \u003cli\u003eMorantz D J, Bilen C S. (1975). Thermoluminescence and induced phosphorescence in irradiated doped PMMA. \u003cem\u003ePolymer\u003c/em\u003e, 16(10), 745-748. https://doi.org/10.1016/0032-3861(75)90192-5\u003c/li\u003e\n \u003cli\u003eShi J, Tao W, Zhou Y, et al. (2024). Air-stable and ultralong room-temperature phosphorescence from doped poly (methyl methacrylate) for visual detection of volatile organic compounds. \u003cem\u003eChemical Engineering Journal\u003c/em\u003e, 498, 155737. https://doi.org/10.1016/j.cej.2024.155737\u003c/li\u003e\n \u003cli\u003eKnyazev A A, Krupin A S, Galyametdinov Y G. (2022). Luminescence behavior of PMMA films doped with Tb (III) and Eu (III) complexes. \u003cem\u003eJournal of Luminescence\u003c/em\u003e, 242, 118609. https://doi.org/10.1016/j.jlumin.2021.118609\u003c/li\u003e\n \u003cli\u003eZheng X, Jiang J, Lin Q, et al. (2023). Excitation-\u0026amp; concentration-dependent color-tunable ultra-long phosphorescence of isophthalonitriles doped polymers. \u003cem\u003eChemical Engineering Journal\u003c/em\u003e, 469, 143929. https://doi.org/10.1016/j.cej.2023.143929\u003c/li\u003e\n \u003cli\u003eYue L, Sun Q, Zhang Y, et al. (2022). Organic phosphor doped thermoplastics with ultralong and memorable room temperature phosphorescence different from crystals. \u003cem\u003eChemical Engineering Journal\u003c/em\u003e, 433, 134307. https://doi.org/10.1016/j.cej.2021.134307\u003c/li\u003e\n \u003cli\u003eZhu Y, Pan M, Ji W, et al. (2025). Modulating room-temperature phosphorescence of D-\u0026pi;-A luminogens via methyl substitution, positional isomerism, and host\u0026ndash;guest doping. \u003cem\u003eSpectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy\u003c/em\u003e, 330, 125763. https://doi.org/10.1016/j.saa.2025.125763\u003c/li\u003e\n \u003cli\u003eZhang Y, Liu J, Sun Q, et al. (2025). Significantly Enhanced Room Temperature Phosphorescence Afterglow via Dopant Isomerization and Doping Strategy. \u003cem\u003eDyes and Pigments\u003c/em\u003e, 113275. https://doi.org/10.1016/j.dyepig.2025.113275\u003c/li\u003e\n \u003cli\u003eZang L, Shao W, Kwon M S, et al. (2020). Photoresponsive luminescence switching of metal‐free organic phosphors doped polymer matrices. \u003cem\u003eAdvanced Optical Materials\u003c/em\u003e, 8(23), 2000654. https://doi.org/10.1002/adom.202000654\u003c/li\u003e\n \u003cli\u003eJiang J, Liu J, Hu C, et al. (2024). Construction and fine tuning of host-guest doping systems and the underlying mechanism of room temperature phosphorescence. \u003cem\u003eDyes and Pigments\u003c/em\u003e, 222, 111931. https://doi.org/10.1016/j.dyepig.2023.111931\u003c/li\u003e\n \u003cli\u003eMa L, Sun S, Ding B, et al. (2021). Highly efficient room‐temperature phosphorescence based on single‐benzene structure molecules and photoactivated luminescence with afterglow. \u003cem\u003eAdvanced Functional Materials\u003c/em\u003e, 31(17), 2010659. https://doi.org/10.1002/adfm.202010659\u003c/li\u003e\n \u003cli\u003eCastex M C, Olivero C, Pichler G, et al. (2006). Fluorescence, room temperature phosphorescence and photodegradation of carbazole compounds in irradiated poly (methyl methacrylate) matrices. \u003cem\u003eSynthetic metals\u003c/em\u003e, 156(9-10), 699-704. https://doi.org/10.1016/j.synthmet.2006.03.015\u003c/li\u003e\n \u003cli\u003eVelasco D S, De Moura A P, Medina A N, et al. (2010). Preparation, characterization, and spectroscopic properties of PC/PMMA doped blends: Study of the effect of rare-earth doping on luminescence, quenching rate, and lifetime enhancement. \u003cem\u003eThe Journal of Physical Chemistry B\u003c/em\u003e, 114(17), 5657-5660. https://doi.org/10.1021/jp911900r\u003c/li\u003e\n \u003cli\u003eChitnis D, Kalyani N T, Dhoble S J. (2019). Comprehensive study on photophysical properties of Eu (TTA) 3bipy phosphor molecularly doped in PMMA and PS matrices. \u003cem\u003eResults in Physics\u003c/em\u003e, 13, 102302. https://doi.org/10.1016/j.rinp.2019.102302\u003c/li\u003e\n \u003cli\u003eDing B, Ma X, Tian H. (2023). Recent advances of pure organic room temperature phosphorescence based on functional polymers. \u003cem\u003eAccounts of Materials Research\u003c/em\u003e, 4(10), 827-838. https://doi.org/10.1021/accountsmr.3c00090\u003c/li\u003e\n \u003cli\u003eLi Y, Han S, Zhao H, et al. (2025). Efficient energy phosphorescence transfer and reversible phosphorescence in aromatic heterocyclic doped systems for advanced information storage. \u003cem\u003eSpectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy\u003c/em\u003e, 336, 126053. https://doi.org/10.1016/j.saa.2025.126053\u003c/li\u003e\n \u003cli\u003eXiong S, Xiong Y, Wang D, et al. (2023). Achieving Tunable Organic Afterglow and UV‐Irradiation‐Responsive Ultralong Room‐Temperature Phosphorescence from Pyridine‐Substituted Triphenylamine Derivatives. \u003cem\u003eAdvanced Materials\u003c/em\u003e, 35(28), 2301874. https://doi.org/10.1002/adma.202301874\u003c/li\u003e\n \u003cli\u003eGan N, Shi H, An Z, et al. (2018). Recent advances in polymer‐based metal‐free room‐temperature phosphorescent materials. \u003cem\u003eAdvanced Functional Materials\u003c/em\u003e, 28(51), 1802657. https://doi.org/10.1002/adfm.201802657\u003c/li\u003e\n \u003cli\u003eYao W, Xiong H, Liao Q, et al. (2024). Promoting organic room temperature phosphorescence through in situ polymerization. \u003cem\u003eJournal of Polymer Science\u003c/em\u003e, 62(2), 401-408. https://doi.org/10.1002/pol.20230442\u003c/li\u003e\n \u003cli\u003eŢucureanu V, Romanițan C, Mihalache I, et al. (2025). PMMA-Au@ YAG: Ce phosphor deposited on flexible substrate for white light emitting devices. \u003cem\u003eMaterials Science and Engineering: B\u003c/em\u003e, 311, 117808. https://doi.org/10.1016/j.mseb.2024.117808\u003c/li\u003e\n \u003cli\u003eGuo J, Hu C, Liu J, et al. (2024). Mechanochromism, tunable pure organic room temperature phosphorescence, single-molecule near-white emission, digital encryption, and anti-counterfeiting. \u003cem\u003eDyes and Pigments\u003c/em\u003e, 221, 111760. https://doi.org/10.1016/j.dyepig.2023.111760\u003c/li\u003e\n \u003cli\u003eLiu H G, Lee Y I, Park S, et al. (2004). Photoluminescent behaviors of several kinds of europium ternary complexes doped in PMMA. \u003cem\u003eJournal of luminescence\u003c/em\u003e, 110(1-2), 11-16. https://doi.org/10.1016/j.jlumin.2004.04.001\u003c/li\u003e\n \u003cli\u003eZhou W, Wang M C, Zhao X. (2015). Poly (methyl methacrylate)(PMMA) doped with DCJTB for luminescent solar concentrator applications. \u003cem\u003eSolar Energy\u003c/em\u003e, 115, 569-576. https://doi.org/10.1016/j.solener.2015.03.012\u003c/li\u003e\n \u003cli\u003eJaffar B M, Swart H C, Ahmed H A A S, et al. (2019). Stability of Bi doped La2O3 powder phosphor and PMMA composites. \u003cem\u003eJournal of Physics and Chemistry of Solids\u003c/em\u003e, 131, 156-163. https://doi.org/10.1016/j.jpcs.2019.04.004\u003c/li\u003e\n \u003cli\u003eM. J. Frisch, G. W.Trucks, H. B.Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, G. Scalmani, V. Barone, G. A. Petersson, H. Nakatsuji, X. Li, M. Caricato, A. V. Marenich, J. Bloino, B. G. Janesko, R. Gomperts, B. Mennucci, H. P. Hratchian, J. V. Ortiz, A. F. Izmaylov, J. L. Sonnenberg, Williams, F. Ding, F. Lipparini, F. Egidi, J. Goings, B. Peng, A. Petrone, T. Henderson, D. Ranasinghe, V. G. Zakrzewski, J. Gao, N. Rega, G. Zheng, W. Liang, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven, K. Throssell, Jr. J. A. Montgomery, J. E. Peralta, F. Ogliaro, M. J. Bearpark, J. J. Heyd, E. N. Brothers, K. N. Kudin, V. N. Staroverov, T. A. Keith, R. Kobayashi, J. Normand, K. Raghavachari, A. P. Rendell, J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, J. M. Millam, M. Klene, C. Adamo, R. Cammi, J. W. Ochterski, R. L. Martin, K. Morokuma, O. Farkas, J. B. Foresman, D. J. Fox, Gaussian 16, Revision C. 01, Gaussian, Inc., Wallingford CT, 2016.\u003c/li\u003e\n \u003cli\u003eNeese, F. (2012). The ORCA program system. \u003cem\u003eWiley Interdisciplinary Reviews: Computational Molecular Science\u003c/em\u003e, 2(1), 73-78. https://doi.org/10.1002/wcms.81\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Scheme","content":"\u003cp\u003eScheme 1 is available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-fluorescence","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jofl","sideBox":"Learn more about [Journal of Fluorescence](https://www.springer.com/journal/10895)","snPcode":"10895","submissionUrl":"https://submission.nature.com/new-submission/10895/3","title":"Journal of Fluorescence","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Phosphorescent Afterglow, Phosphorescence Lifetime, PMMA Doping, Heavy atoms, Rigid structure","lastPublishedDoi":"10.21203/rs.3.rs-8602735/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8602735/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSmall-molecule phosphorescent materials feature high chemical purity and tailorable luminescence, yet aggregation-caused quenching (ACQ) and poor thermal stability remain critical bottlenecks. Herein, we designed and synthesized a series of carbazole-based derivatives (\u003cb\u003eK-CN\u003c/b\u003e, \u003cb\u003eK-Br₂\u003c/b\u003e, \u003cb\u003eK-Cl\u003c/b\u003e, \u003cb\u003eK-Br\u003c/b\u003e), These compounds have heavy - atom substituents (\u0026ndash;Br, \u0026ndash;Cl) and a rigid structure to enhance spin orbit coupling for efficient intersystem crossing. The rigid carbazole backbone suppresses non - radiative decay, and the optimized molecular structure avoids quenching. which exhibit relative extended phosphorescent afterglow durations (0.6-3 s), and long phosphorescence lifetimes (\u003cem\u003eτ\u003c/em\u003e\u003csub\u003e\u003cem\u003ep\u003c/em\u003e\u003c/sub\u003e: 4.2-177.3 ms) at 77 K. Doping these compounds into a PMMA matrix yields composite materials with significantly enhanced room-temperature phosphorescence. \u003cb\u003eK-CN\u003c/b\u003e stands out with the longest lifetime (177.3 ms) and room-temperature phosphorescent afterglow (2 s), and favorable energy level gaps (S₁\u0026ndash;T₅ \u0026asymp; 0.158 eV) via TD-DFT calculations. which hold great potential for applications in optoelectronic devices such as organic light-emitting diodes (OLEDs).\u003c/p\u003e","manuscriptTitle":"Dual-Mechanism Synergistic Enhancement of Room-Temperature Phosphorescence in Carbazole Derivatives","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-17 09:54:51","doi":"10.21203/rs.3.rs-8602735/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-03-03T11:53:16+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-27T23:08:38+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"79088337980879271561160223215797663738","date":"2026-02-16T22:26:29+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"151299383900134490357420767237327284950","date":"2026-02-16T12:44:36+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-11T17:50:14+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-06T04:45:16+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-06T04:39:56+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Fluorescence","date":"2026-01-14T14:08:44+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-fluorescence","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jofl","sideBox":"Learn more about [Journal of Fluorescence](https://www.springer.com/journal/10895)","snPcode":"10895","submissionUrl":"https://submission.nature.com/new-submission/10895/3","title":"Journal of Fluorescence","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"90075f8d-ae89-4884-b10d-4107a7586527","owner":[],"postedDate":"February 17th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-03-30T16:19:55+00:00","versionOfRecord":{"articleIdentity":"rs-8602735","link":"https://doi.org/10.1007/s10895-026-04749-w","journal":{"identity":"journal-of-fluorescence","isVorOnly":false,"title":"Journal of Fluorescence"},"publishedOn":"2026-03-27 16:13:24","publishedOnDateReadable":"March 27th, 2026"},"versionCreatedAt":"2026-02-17 09:54:51","video":"","vorDoi":"10.1007/s10895-026-04749-w","vorDoiUrl":"https://doi.org/10.1007/s10895-026-04749-w","workflowStages":[]},"version":"v1","identity":"rs-8602735","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8602735","identity":"rs-8602735","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}