Abstract

Benzo[1,2-b:4,5-b′]dithiophene (BDT) has been widely used to construct donor-acceptor (D-A) copolymers in organic solar cells (OSCs). However, benzo[1,2-b:4,5-b′]difuran (BDF), an analogue of BDT, has received less attention than BDT. The photovoltaic performance of BDF copolymers has lagged behind that of BDT copolymers. Here, we designed and synthesized two BDF copolymers, PBF1-C and PBF1-C-2Cl. PBF1-C-2Cl, which is composed of BDF and benzo[1,2-c:4,5-c′]dithiophene-4,8-dione connected by a chlorinated thiophene π-bridge, displays a low-lying highest occupied molecular orbital energy level, which helps in yielding a high open-circuit voltage (V_oc) in OSCs. As a result, when blended with Y6, PBF1-C-2Cl-based devices showed a high V_oc of 0.83 V and a power conversion efficiency (PCE) of 13.10%. To the best of our knowledge, the PCE of 13.10% is among the highest efficiency values for OSCs based on BDF copolymers.

中文翻译：

---

基于氯官能化苯并[1,2-b：4,5-b']二呋喃-苯并[1,2-c：4,5-c']二噻吩-4,8-​​二酮共聚物的有机太阳能电池，其效率超过13％

摘要

苯并[1,2- b：4,5- b ']二噻吩（BDT）已被广泛用于构建有机太阳能电池（OSC）中的供体-受体（DA）共聚物。然而，苯并[1,2- b：4,5- b ']二呋喃（BDF），一种BDT的类似物，受到的关注少于BDT。BDF共聚物的光伏性能落后于BDT共聚物。在这里，我们设计并合成了两种BDF共聚物PBF1-C和PBF1-C-2Cl。由BDF和通过氯化噻吩π-桥连接的苯并[1,2- c：4,5- c ']二噻吩-4,8-​​dione组成的PBF1-C-2Cl显示出低洼的最高占据分子轨道能级，有助于产生高开路电压（V _oc）。结果，当与Y6掺混时，基于PBF1-C-2Cl的器件显示出0.83V的高V _oc和13.10％的功率转换效率（PCE）。据我们所知，PCE为13.10％，是基于BDF共聚物的OSC的最高效率值之一。