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Side-Chains Engineered Self-Assembly of Ortho-Benzodipyrrole-Based Acceptors: Comprehensive Exploration of Structure-Interface-Photovoltaics Correlations
   

Side-Chains Engineered Self-Assembly of Ortho-Benzodipyrrole-Based Acceptors: Comprehensive Exploration of Structure-Interface-Photovoltaics Correlations

Yung-Jing Xue, Chen-Yu Chang, Chieh-Ming Hung, Chi-Chun Tseng, Je-Wei Chang, Chun-Jen Su, Chia-Lin Tsai, Han-Cheng Lu, Kuo-Hsiu Huang, Kuei-Yu Tai, …
Advanced functional materials, Vol.35(49), e04705
01/12/2025
Chemistry Chemistry, Multidisciplinary Chemistry, Physical Materials Science, Multidisciplinary Nanoscience & Nanotechnology Physics, Applied Physics, Condensed Matter Science & Technology Science & Technology - Other Topics Materials Science Physical Sciences Physics Technology
This research employs inner side-chain engineering in C-shaped ortho-benzodipyrrole-based (CB) A-D-A non-fullerene acceptors (NFAs) CB8, CB12, CB16, and CB20, where side-chain configuration crucially influences self-assembly, single-crystal structures, and optoelectronic properties. The enthalpy of fusion at the melting point, combined with the intensity of the 730 nm solid-state absorption shoulder, suggests that the acceptor-acceptor (A-A) interactions follow the order: CB8 > CB12 > CB20 > CB16. Solution small- and wide-angle X-ray scattering (SWAXS) quantitatively reveals the successively increased donor-acceptor (D-A) association numbers of these CB derivatives with PM6, consistent with the reduction of their A-A self-assembly. Complementarily and comprehensively, transient absorption spectroscopy (TAS) shows a systematically shortened decay-time of charge transfer in the series of the binary PM6:CB (1:1.2 wt%) thin films, from 25.40 ps (CB8), to 16.13 ps (CB12), to 15.03 ps (CB20), and to 11.97 ps (CB16), following the increasing trend of CB-PM6 interaction strength. Correspondingly, the photovoltaic efficiency improves with the enhanced CB-PM6 interactions from PM6:CB8 (15.24%), to PM6:CB12 (16.66%), to PM6:CB20 (17.12%), and to PM6:CB16 (18.13%). These close correlations between the structures and photovoltaic properties elucidate the importance of minimizing A-A self-aggregation and enhancing D (PM6)-A (CBs) interactions via engineering the side chains in the CB-based acceptors.

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url
https://doi.org/10.1002/adfm.202504705
Published (Version of record)

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