Perylene Diimide-Fused Dithiophenepyrroles with Different End Groups as Acceptors for Organic Photovoltaics

作者：Yu‐Che Lin, Nian‐Zu She, Chung‐Hao Chen, Atsushi Yabushita, Heng Lin, Menghua Li, Bin Chang, Ting‐Fang Hsueh, Bing‐Shiun Tsai, Po‐Tuan Chen, Yang Yang, Kung‐Hwa Wei · 发表于：ACS Applied Materials & Interfaces · 年份：2022 · DOI：10.1021/acsami.2c06135 · 被引用次数：29 · 研究领域：Organic Electronics and Photovoltaics、Perovskite Materials and Applications、Conducting polymers and applications

In this study, we synthesized four new A-DA'D-A acceptors (where A and D represent acceptor and donor chemical units) incorporating perylene diimide units (A') as their core structures and presenting various modes of halogenation and substitution of the functional groups at their end groups (A). In these acceptors, by fusing dithiophenepyrrole (DTP) moieties (D) to the helical perylene diimide dimer (hPDI) to form fused-hPDI (FhPDI) cores, we could increase the D/A' oscillator strength in the cores and, thus, the intensity of intramolecular charge transfer (ICT), thereby enhancing the intensity of the absorption bands. With four different end group units─IC2F, IC2Cl, IO2F, and IO2Cl─tested, each of these acceptor molecules exhibited different optical characteristics. Among all of these systems, the organic photovoltaic device incorporating the polymer PCE10 blended with the acceptor FhPDI-IC2F (1:1.1 wt %) had the highest power conversion efficiency (PCE) of 9.0%; the optimal PCEs of PCE10:FhPDI-IO2F, PCE10:FhPDI-IO2Cl, and PCE10:FhPDI-IC2Cl (1:1.1 wt %) devices were 5.2, 4.7, and 7.7%, respectively. The relatively high PCE of the PCE10:FhPDI-IC2F device resulted primarily from the higher absorption coefficients of the FhPDI-IC2F acceptor, lower energy loss, and more efficient charge transfer; the FhPDI-IC2F system experienced a lower degree of geminate recombination─as a result of improved delocalization of π-electrons along the acceptor unit─relative to that of the other th...