Solution‐processed bulk‐heterojunction polymer solar cells (PSCs) are indispensable in photovoltaics. π‐Conjugated donor–acceptor copolymers as electron donors have become the cornerstone as the most intensively studied topic in this field. Thieno[3,4‐c]pyrrole‐4,6‐dione (TPD) is one of the most commonly used electron‐withdrawing moieties. Based on TPD, a new building block, 1,3‐bis(thieno[3,4‐b]thiophen‐6‐yl)‐4H‐thieno[3,4‐c]pyrrole‐4,6(5H)‐dione (TBTT), is designed and a novel low‐bandgap TPD‐copolymer is developed with a power conversion efficiency (PCE) up to 7.5% with a low open‐circuit voltage (V_oc) of 0.633 V when utilizing PC₇₁BM as electron acceptor. To promote the performance of TBTT‐based polymers, four conjugated copolymers are designed and synthesized based on TBTT and benzodithiophene (BDT) building blocks by regulating their steric hindrance with side alkyl chains on BDT moiety. PSCs based on polymer P4 with an additional n‐hexyl side chain blended with PC₇₁BM deliver a high PCE of 9.1% with a V_oc of 0.78 V increased by 24%, which is among the highest in TPD‐based polymers. The study provides new insights into the molecular design and synthesis of high‐performance photovoltaic materials.

中文翻译：

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向高性能1,3-双（噻吩并[3,4-b]噻吩-6-基）-4H-噻吩并[3,4-c]吡咯-4,6（5H）-二酮-的立体定向调制具有增强的开路电压的基于聚合物的太阳能电池

溶液处理的本体异质结聚合物太阳能电池（PSC）在光伏中不可或缺。作为电子给体的π共轭给体-受体共聚物已成为该领域研究最深入的基础。Thieno [3,4- c ]吡咯-4,6-二酮（TPD）是最常用的吸电子部分之一。基于TPD，一个新的构建基块1,3-双（thieno [3,4- b ]噻吩-6-yl）-4 H - thieno [3,4 - c ]吡咯-4,6（5 H）设计了二酮（TBTT），并开发了一种新型的低带隙TPD共聚物，使用PC ₇₁时，其功率转换效率（PCE）高达7.5％，开路电压（V _oc）低至0.633 VBM作为电子受体。为了提高基于TBTT的聚合物的性能，基于TBTT和苯并二噻吩（BDT）结构单元，通过调节BDT部分的侧烷基链的位阻，设计并合成了四种共轭共聚物。基于聚合物P4的PSC与PC ₇₁ BM混合有一个正己基侧链，可提供9.1％的高PCE ，0.78 V的V _oc增加了24％，这在TPD基聚合物中是最高的。该研究为高性能光伏材料的分子设计和合成提供了新的见解。