We introduced 3-octylthiophene (OT) or 3-octylthieno [3,2-b]thiophene (OTT) as π-bridges into PBT (poly(1-(4,8-bis(5- (2-ethylhexyl)selenophen-2-yl)benzo[1,2-b:4,5-b']dithiophen-2-yl)-5-(2-butyloctyl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione), which is based on benzodithiophene and thienopyrrolodione units, in order to prepare thiophene-based π-bridging donor-acceptor conjugated copolymers for use as hole-transport layers in perovskite solar cells (PeSCs). The resulting polymers exhibit strengthened intermolecular π-π stacking and increased crystallinity (dominant face-on orientation), which facilitates vertical charge transport and hole mobility. Moreover, the highest occupied molecular orbital level of PBT-OTT is similar to the valence band of the perovskite material. As a result, efficient hole extraction occurs with reduced charge carrier recombination in PBT-OTT-based PeSCs. Therefore, the introduction of π-bridges to extend the π-conjugation length of conjugated polymers is a promising strategy for the development of efficient hole-transporting materials for use in PeSCs.

我们将3-辛基噻吩（OT）或3-辛基噻吩并[3,2-b]噻吩（OTT）作为π桥引入PBT（poly（1-（4,8-bis（5-（2-ethylhexyl）selenophen- 2-基）苯并[1,2-b：4,5-b']二噻吩-2-基）-5-（2-丁基辛基）-4H-硫代[3,4-c]吡咯-4,6基于苯并二噻吩和噻吩并吡咯二酮单元的5H）-dione），以制备噻吩基π桥供体-受体共轭共轭共聚物，用作钙钛矿太阳能电池（PeSCs）的空穴传输层。分子间π-π堆积和增加的结晶度（显着的面朝取向），这有助于垂直电荷传输和空穴迁移；此外，PBT-OTT的最高占据分子轨道能级与钙钛矿材料的价带相似。结果，在基于PBT-OTT的PeSC中，在减少载流子重组的情况下发生了有效的空穴提取。因此，引入π桥以延长共轭聚合物的π共轭长度是开发用于PeSC的有效空穴传输材料的有前途的策略。