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A Facile Synthesized Polymer Featuring B‐N Covalent Bond and Small Singlet‐Triplet Gap for High‐Performance Organic Solar Cells
Author(s) -
Pang Shuting,
Wang Zhiqiang,
Yuan Xiyue,
Pan Langheng,
Deng Wanyuan,
Tang Haoran,
Wu Hongbin,
Chen Shanshan,
Duan Chunhui,
Huang Fei,
Cao Yong
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202016265
Subject(s) - organic solar cell , singlet state , materials science , band gap , crystallinity , acceptor , covalent bond , energy conversion efficiency , polymer , organic semiconductor , miscibility , photochemistry , solar cell , chemistry , optoelectronics , atomic physics , organic chemistry , excited state , physics , composite material , condensed matter physics
Abstract High‐efficiency organic solar cells (OSCs) largely rely on polymer donors. Herein, we report a new building block BNT and a relevant polymer PBNT‐BDD featuring B‐N covalent bond for application in OSCs. The BNT unit is synthesized in only 3 steps, leading to the facile synthesis of PBNT‐BDD. When blended with a nonfullerene acceptor Y6‐BO, PBNT‐BDD afforded a power conversion efficiency (PCE) of 16.1 % in an OSC, comparable to the benzo[1,2‐b:4,5‐b′]dithiophene (BDT)‐based counterpart. The nonradiative recombination energy loss of 0.19 eV was afforded by PBNT‐BDD. PBNT‐BDD also exhibited weak crystallinity and appropriate miscibility with Y6‐BO, benefitting of morphological stability. The singlet–triplet gap (Δ E ST ) of PBNT‐BDD is as low as 0.15 eV, which is much lower than those of common organic semiconductors (≥0.6 eV). As a result, the triplet state of PBNT‐BDD is higher than the charge transfer (CT) state, which would suppress the recombination via triplet state effectively.