Carbon–Nitrogen Axial Chirality as a Novel Chiral Framework Design Strategy for Circularly Polarized Luminescence Materials

Abstract

Circularly polarized luminescence (CPL) materials are essential for advanced optoelectronic applications, yet efficient chiral design strategies remain challenging. Axial chirality has been widely employed in the construction of CPL materials due to its unique rigid structure. However, the focus has been primarily on the derivatives of carbon–carbon axial chirality. We herein propose a strategy for constructing carbon–nitrogen (C─N) axially chiral molecular frameworks to fully exploit the excellent chromophoric properties of nitrogen-containing heterocycles (such as carbazole). A pair of chiral emitters, (S/R)-AI-2TCFC, was designed and synthesized, exhibiting an emission peak at 578 nm both in the toluene solution and in the neat film state. It possessed typical aggregation-induced emission (AIE), thermally activated delayed fluorescence (TADF), and a luminescence dissymmetry factor (g_lum) of 10⁻³, demonstrating its potential for high-performance device applications. These materials were successfully applied in circularly polarized organic light-emitting diodes (CP-OLEDs), demonstrating promising electroluminescence performance. This innovative strategy not only expands the design toolbox for CPL materials but also paves the way for next-generation high-performance optoelectronic devices.

Keywords

aggregation-induced emission / carbon–nitrogen axial chirality / chiral strategy / circularly polarized luminescence

References

[1] F. Song, Z. Xu, Q. Zhang, et al., “Highly Efficient Circularly Polarized Electroluminescence From Aggregation-Induced Emission Luminogens With Amplified Chirality and Delayed Fluorescence,” Advanced Functional Materials 28 (2018): 1800051.

[2] X.-F. Luo, S.-Q. Song, X. Wu, C.-F. Yip, S. Cai, and Y.-X. Zheng, “A chiral Spirofluorene-Embedded Multiple-Resonance Thermally Activated Delayed Fluorescence Emitter for Efficient Pure-Green Circularly Polarized Electroluminescence,” Aggregate 5 (2024): e445.

[3] M. Schadt, “Liquid Crystal Materials And Liquid Crystal Displays,” Annual Review of Materials Science 27 (1997): 305-379.

[4] K. Liao, X. Hu, Y. Cheng, et al., “Spintronics of Hybrid Organic-Inorganic Perovskites: Miraculous Basis of Integrated Optoelectronic Devices,” Advanced Optical Materials 7 (2019): 1900350.

[5] J. Zhao and P. Xing, “Regulation of Circularly Polarized Luminescence in Multicomponent Supramolecular Coassemblies,” ChemPhotoChem 6 (2022): e202100124.

[6] J. F. Sherson, H. Krauter, R. K. Olsson, et al., “Quantum Teleportation Between Light and Matter,” Nature 443 (2006): 557-560.

[7] X. Yang, X. Gao, Y.-X. Zheng, et al., “Recent Progress of Circularly Polarized Luminescence Materials From Chinese Perspectives,” CCS Chemistry 5 (2023): 2760-2789.

[8] D. Barman, K. Narang, R. Gogoi, D. Barman, and P. K. Iyer, “Exceptional Class of Thermally Activated Delayed Fluorescent Emitters That Display Pure Blue, Near-IR, Circularly Polarized Luminescence and Multifunctional Behaviour for Highly Efficient and Stable OLEDs,” Journal of Materials Chemistry C 10 (2022): 8536-8583.

[9] X. Wang, S. Ma, B. Zhao, and J. Deng, “Frontiers in Circularly Polarized Phosphorescent Materials,” Advanced Functional Materials 33 (2023): 2214364.

[10] C. Zhang, S. Li, X.-Y. Dong, and S.-Q. Zang, “Circularly Polarized Luminescence of Agglomerate Emitters,” Aggregate 2 (2021): e48.

[11] C. Qi, K. Wei, Q. Li, et al., “Visualization of Enantioselective Recognition and Separation of Chiral Acids by Aggregation-Induced Emission Chiral Diamine,” Aggregate 4 (2023): e299.

[12] L. Zhang, T. Wang, J. Jiang, and M. Liu, “Chiral Porphyrin Assemblies,” Aggregate 4 (2023): e198.

[13] H. Yan, Y. He, D. Wang, T. Han, and B. Z. Tang, “Aggregation-Induced Emission Polymer Systems With Circularly Polarized Luminescence,” Aggregate 4 (2023): e331.

[14] B.-H. Liu, Y. Zong, N. Liu, and Z.-Q. Wu, “Advances in Self-Assembly-Based Circularly Polarized Luminescent Materials,” Science China Chemistry 67 (2024): 3247-3257.

[15] S.-Y. Li, B.-H. Duan, N. Liu, J. Luo, Z. Chen, and Z.-Q. Wu, “Helical Star-Shaped Bottlebrush Polymers: From Controlled Synthesis to Tunable Photoluminescence and Circularly Polarized Luminescence,” ACS Macro Letters Journal 13 (2024): 1396-1402.

[16] N. Liu, R.-T. Gao, and Z.-Q. Wu, “Helix-Induced Asymmetric Self-Assembly of π-Conjugated Block Copolymers: From Controlled Syntheses to Distinct Properties,” Accounts of Chemical Research Journal 56 (2023): 2954-2967.

[17] J. Lin, R. Liu, P. Chen, et al., “Stimulating and Harnessing Circularly Polarized Luminescence of Helically Assembled Carbonized Polymer Dots via Interfacial Dynamics,” Aggregate 4 (2023): e311.

[18] T. Zhang, Y. Zhang, Z. He, et al., “Recent Advances of Chiral Isolated and Small Organic Molecules: Structure and Properties for Circularly Polarized Luminescence,” Chemistry-An Asian Journal 19 (2024): e202400049.

[19] J. R. Brandt, F. Salerno, and M. J. Fuchter, “The added Value of Small-Molecule Chirality in Technological Applications,” Nature Reviews Chemistry 1 (2017): 0045.

[20] X. Li, Y. Xie, and Z. Li, “The Progress of Circularly Polarized Luminescence in Chiral Purely Organic Materials,” Advanced Photonics Research 2 (2021): 2000136.

[21] A. Jiang, H. Cui, L. Zhang, et al., “Functionalization of the Octahydro-Binaphthol Skeleton: A Universal Strategy for Directly Constructing D-A Type Axially Chiral Biphenyl Luminescent Molecules,” Journal of Organic Chemistry 89 (2024): 3605-3611.

[22] J. Feng, L. Fu, H. Geng, W. Jiang, and Z. Wang, “Designing a Near-Infrared Circularly Polarized Luminescent Dye by Dissymmetric Spiro-Fusion,” Chemical Communications 56 (2020): 912-915.

[23] X.-F. Luo, H.-B. Han, Z.-P. Yan, et al., “Multicolor Circularly Polarized Photoluminescence and Electroluminescence With 1,2-Diaminecyclohexane Enantiomers,” ACS Applied Materials and Interfaces Journal 12 (2020): 23172-23180.

[24] T. Imagawa, S. Hirata, K. Totani, T. Watanabe, and M. Vacha, “Thermally Activated Delayed Fluorescence With Circularly Polarized Luminescence Characteristics,” Chemical Communications 51 (2015): 13268-13271.

[25] M. Li, S.-H. Li, D. Zhang, et al., “Stable Enantiomers Displaying Thermally Activated Delayed Fluorescence: Efficient OLEDs With Circularly Polarized Electroluminescence,” Angewandte Chemie International Edition 57 (2018): 2889-2893.

[26] Y.-F. Wang, M. Li, J.-M. Teng, H.-Y. Zhou, W.-L. Zhao, and C.-F. Chen, “Chiral TADF-Active Polymers for High-Efficiency Circularly Polarized Organic Light-Emitting Diodes,” Angewandte Chemie International Edition 60 (2021): 23619-23624.

[27] W.-C. Guo, W.-L. Zhao, K.-K. Tan, M. Li, and C.-F. Chen, “B,N-Embedded Hetero[9]Helicene Toward Highly Efficient Circularly Polarized Electroluminescence,” Angewandte Chemie International Edition 63 (2024): e202401835.

[28] Y. Liu, Z. Ma, Z. Wang, and W. Jiang, “Boosting Circularly Polarized Luminescence Performance by a Double π-Helix and Heteroannulation,” Journal of the American Chemical Society 144 (2022): 11397-11404.

[29] L. Zhang, I. Song, J. Ahn, et al., “π-Extended Perylene Diimide Double-Heterohelicenes as Ambipolar Organic Semiconductors for Broadband Circularly Polarized Light Detection,” Nature Communications 12 (2021): 142.

[30] J. Malinčík, S. Gaikwad, J. P. Mora-Fuentes, et al., “Circularly Polarized Luminescence in a Möbius Helicene Carbon Nanohoop,” Angewandte Chemie International Edition 61 (2022): e202208591.

[31] Y. Morisaki, M. Gon, T. Sasamori, N. Tokitoh, and Y. Chujo, “Planar Chiral Tetrasubstituted [2.2]Paracyclophane: Optical Resolution and Functionalization,” Journal of the American Chemical Society 136 (2014): 3350-3353.

[32] X.-J. Liao, D. Pu, L. Yuan, et al., “Planar Chiral Multiple Resonance Thermally Activated Delayed Fluorescence Materials for Efficient Circularly Polarized Electroluminescence,” Angewandte Chemie International Edition 62 (2023): e202217045.

[33] M. Gon, Y. Morisaki, and Y. Chujo, “Optically Active Cyclic Compounds Based on Planar Chiral [2.2]Paracyclophane: Extension of the Conjugated Systems and Chiroptical Properties,” Journal of Materials Chemistry C 3 (2015): 521-529.

[34] J.-M. Teng, D.-W. Zhang, and C.-F. Chen, “Recent Progress in Circularly Polarized Luminescence of [2.2]Paracyclophane Derivatives,” ChemPhotoChem 6 (2022): e202100228.

[35] M. Li, W.-B. Lin, L. Fang, and C.-F. Chen, “Recent Progress on Circularly Polarized Luminescence of Chiral Organic Small Molecules,” Acta Chimica Sinica 75 (2017): 1150.

[36] E. M. Sánchez-Carnerero, A. R. Agarrabeitia, F. Moreno, et al., “Circularly Polarized Luminescence From Simple Organic Molecules,” Chemistry-A European Journal 21 (2015): 13488-13500.

[37] S.-P. Wan, H.-Y. Lu, M. Li, and C.-F. Chen, “Advances in Circularly Polarized Luminescent Materials Based on Axially Chiral Compounds,” Journal of Photochemistry and Photobiology C 50 (2022): 100500.

[38] H. Lu, J. Mack, T. Nyokong, N. Kobayashi, and Z. Shen, “Optically Active BODIPYs,” Coordination Chemistry Reviews 318 (2016): 1-15.

[39] Y. Li, J. Liang, S. Fu, et al., “Full-Color-Tunable Chiral Aggregation-Induced Emission Fluorophores With Tailored Propeller Chirality and Their Circularly Polarized Luminescence,” Aggregate 5 (2024): e613.

[40] D. Liu, W.-J. Wang, P. Alam, et al., “Highly Efficient Circularly Polarized Near-Infrared Phosphorescence in Both Solution and Aggregate,” Nature Photonics 18 (2024): 1276-1284.

[41] S. Feuillastre, M. Pauton, L. Gao, et al., “Design and Synthesis of New Circularly Polarized Thermally Activated Delayed Fluorescence Emitters,” Journal of the American Chemical Society 138 (2016): 3990-3993.

[42] Z.-B. Sun, J.-K. Liu, D.-F. Yuan, et al., “2,2′-Diamino-6,6′-Diboryl-1,1′-Binaphthyl: A Versatile Building Block for Temperature-Dependent Dual Fluorescence and Switchable Circularly Polarized Luminescence,” Angewandte Chemie International Edition 58 (2019): 4840-4846.

[43] Z.-P. Yan, L. Yuan, Y. Zhang, et al., “A Chiral Dual-Core Organoboron Structure Realizes Dual-Channel Enhanced Ultrapure Blue Emission and Highly Efficient Circularly Polarized Electroluminescence,” Advanced Materials 34 (2022): 2204253.

[44] M. Li, Y.-F. Wang, D. Zhang, L. Duan, and C.-F. Chen, “Axially Chiral TADF-Active Enantiomers Designed for Efficient Blue Circularly Polarized Electroluminescence,” Angewandte Chemie International Edition 59 (2020): 3500-3504.

[45] C.-H. Guo, W.-L. Zhao, K.-K. Tan, et al., “Axial Enantiomers With Donor-Regulated TADF Feature for Multicolor Circularly Polarized Electroluminescence,” Science China Chemistry 67 (2024): 2039-2045.

[46] X.-Z. Wang, S. Xing, X. Xiao, L. Yuan, Z.-Y. Hou, and Y.-X. Zheng, “Axial Chiral Biphenyl MR-TADF Enantiomers for Efficient Narrowband Circularly Polarized Electroluminescence,” Advanced Functional Materials 35 (2025): 2412044.

[47] L. Yuan, J.-W. Xu, Z.-P. Yan, et al., “Tetraborated Intrinsically Axial Chiral Multi-resonance Thermally Activated Delayed Fluorescence Materials,” Angewandte Chemie International Edition 63 (2024): e202407277.

[48] L. Jin, Y. Li, Y. Mao, et al., “Chiral Dinitrogen Ligand Enabled Asymmetric Pd/Norbornene Cooperative Catalysis Toward the Assembly of C-N Axially Chiral Scaffolds,” Nature Communications 2024, 15: 4908.

[49] B.-J. Wang, G.-X. Xu, Z.-W. Huang, et al., “Single-Step Synthesis of Atropisomers With Vicinal C−C and C−N Diaxes by Cobalt-Catalyzed Atroposelective C−H Annulation,” Angewandte Chemie International Edition 61 (2022): e202208912.

[50] O. M. Musa, ed., Handbook of Maleic Anhydride Based Materials (Springer International Publishing, 2016).

[51] T. Kim, G. Shin, T. Park, and M. Kim, “Molecular Design Leveraging Non-Covalent Interactions for Efficient Light-Emitting Organic Small Molecules,” Advanced Functional Materials 35 (2024): 2412267.

[52] A. J. Neel, M. J. Hilton, M. S. Sigman, and F. D. Toste, “Exploiting Non-Covalent π interactions for Catalyst Design,” Nature 543 (2017): 637-646.

[53] E. C. Lee, D. Kim, P. Jurecˇka, P. Tarakeshwar, P. Hobza, and K. S. Kim, “Understanding of Assembly Phenomena by Aromatic−Aromatic Interactions:  Benzene Dimer and the Substituted Systems,” Journal of Physical Chemistry A 111 (2007): 3446-3457.

[54] S. M. Melikova, A. P. Voronin, J. Panek, et al., “Interplay of π-Stacking and Inter-Stacking Interactions in Two-Component Crystals of Neutral Closed-Shell Aromatic Compounds: Periodic DFT study,” RSC Advances 10 (2020): 27899-27910.

[55] Q. Xue and G. Xie, “Thermally Activated Delayed Fluorescence Beyond Through-Bond Charge Transfer for High-Performance OLEDs,” Advanced Optical Materials 9 (2021): 2002204.

[56] H. Lee, D. Karthik, R. Lampande, J. H. Ryu, and J. H. Kwon, “Recent Advancement in Boron-Based Efficient and Pure Blue Thermally Activated Delayed Fluorescence Materials for Organic Light-Emitting Diodes,” Frontiers in Chemistry 8 (2020): 373.

[57] T.-T. Bui, F. Goubard, M. IbrahimOuali, D. Gigmes, F. Dumur, and Beilstein, “Recent Advances on Organic Blue Thermally Activated Delayed Fluorescence (TADF) Emitters for Organic Light-Emitting Diodes (OLEDs),” Journal of Organic Chemistry 14 (2018): 282-308.

[58] J. Huang, H. Nie, J. Zeng, et al., “Highly Efficient Nondoped OLEDs With Negligible Efficiency Roll-Off Fabricated From Aggregation-Induced Delayed Fluorescence Luminogens,” Angewandte Chemie International Edition 56 (2017): 12971-12976.

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2025 The Author(s). Aggregate published by SCUT, AIEI, and John Wiley & Sons Australia, Ltd.