Dithienopyrrole Cored p‐Type Semiconductors Enabling 20% Efficiency Dopant‐Free Perovskite Solar Cells

• Published in: Angewandte Chemie International Edition 2019-09, Vol.58 (39), p.13717-13721
• Main Authors: Zhou, Jie, Yin, Xinxing, Dong, Zihao, Ali, Amjad, Song, Zhaoning, Shrestha, Niraj, Sandip Singh Bista, Bao, Qinye, Ellingson, Randy J, Yanfa Yan, Tang, Weihua
• Format: Article
• Language: English
• Subjects: Alkylation; Conjugation; Dopants; Efficiency; Electronics industry; Energy conversion efficiency; Hole mobility; Molecular orbitals; Organic semiconductors; P-type semiconductors; Perovskites; Photoluminescence; Photons; Photovoltaic cells; Semiconductors; Solar cells
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201905624

Organic p‐type semiconductors with tunable structures offer great opportunities for hybrid perovskite solar cells (PVSCs). We report herein two dithieno[3,2‐b:2′,3′‐d]pyrrole (DTP) cored molecular semiconductors prepared through π‐conjugation extension and an N‐alkylation strategy. The as‐prepared conjugated molecules exhibit a highest occupied molecular orbital (HOMO) level of −4.82 eV and a hole mobility up to 2.16×10−4 cm2 V−1 s−1. Together with excellent film‐forming and over 99 % photoluminescence quenching efficiency on perovskite, the DTP based semiconductors work efficiently as hole‐transporting materials (HTMs) for n‐i‐p structured PVSCs. Their dopant‐free MA0.7FA0.3PbI2.85Br0.15 devices exhibit a power conversion efficiency over 20 %, representing one of the highest values for un‐doped molecular HTMs based PVSCs. This work demonstrates the great potential of using a DTP core in designing efficient semiconductors for dopant‐free PVSCs.