聚合物
材料科学
亚胺
带隙
结晶度
能量转换效率
接受者
聚合物太阳能电池
聚合物混合物
光电子学
化学工程
共聚物
化学
有机化学
复合材料
催化作用
工程类
物理
凝聚态物理
作者
Zhiping Cao,Jiale Chen,Shengjian Liu,Minchao Qin,Tao Jia,Jiaji Zhao,Qingduan Li,Lei Ying,Yue‐Peng Cai,Xinhui Lu,Fei Huang,Yong Cao
标识
DOI:10.1021/acs.chemmater.9b03570
摘要
All-polymer solar cells (all-PSCs) are proven to possess outstanding thermal and mechanical stabilities. However, concurrently achieving appropriate phase-separated pattern, efficient charge transportation, and adequate charge transfer between donor and acceptor components is still a challenge, and thus, only a few polymer–polymer bulk heterojunction (BHJ) blends have yielded BHJ device power conversion efficiency (PCE) values of >8%. Generally, polymer backbone substitutions may have a direct influence on the device performance. Thus, this report examines a set of wide bandgap polymer donor analogues composed of thienothiophene (TT) or thiazolothiazole (TTz) motif, and their all-PSC device performance with N2200. Results show that all-PSCs based on the imine-substituted derivative PBDT-TTz exhibit PCE values as high as 8.4%, which largely outperform the analogue PBDT-TT-based ones with PCEs of only 0.7%. This work reveals that the imine substitution in polymer backbones of PBDT-TTz not only increases the ionization potential (IP) and electron affinity (EA), narrows the optical gap (Eopt), but also has significantly impacts on the BHJ film morphologies. PBDT-TTz:N2200 BHJ blends present better miscibility, suppressed phase separation, much stronger crystallinity, and face-on ordering, which contribute to efficient exciton dissociation, charge transportation, and therefore, high-efficiency in all-PSCs. This study demonstrates that the imine-substituted polymers composed of TTz motif, which can be easily synthesized through a facile two-step procedure, are a promising class of wide-bandgap polymer donors for efficient all-PSCs.
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