Mechanically robust and stretchable organic solar cells plasticized by small-molecule acceptors
Zhenye Wang, Zhenye Wang, Di Zhang, Lvpeng Yang, Lvpeng Yang, Omar Allam, Yerun Gao, Yang Su, Meichen Xu, Songmin Mo, Qinghe Wu, Zhi Wang, Zhi Wang, Junfeng Liu, Jiayi He, Rui Li, Xingwang Jia, Zhilin Li, Long Yang, Long Yang, Mark Weber, Yu Yu, Xinliang Zhang, Tobin J. Marks, Natalie Stingelin, Josh Kacher, Seung Soon Jang, Antonio Facchetti, Ming Shao
Abstract
Emerging wearable devices would benefit from integrating ductile photovoltaic light-harvesting power sources. In this work, we report a small-molecule acceptor (SMA), also known as a non–fullerene acceptor (NFA), designed for stretchable organic solar cell ( s -OSC) blends with large mechanical compliance and performance. Blends of the organosilane-functionalized SMA BTP-Si4 with the polymer donor PNTB6-Cl achieved a power conversion efficiency (PCE) of >16% and ultimate strain (ε u ) of >95%. Typical SMAs suppress OSC blend ductility, but the addition of BTP-Si4 enhances it. Although BTP-Si4 is less crystalline than other SMAs, it retains considerable electron mobility and is highly miscible with PNTB6-Cl and is essential for enhancing ε u . Thus, s -OSCs with PCE > 14% and operating normally under various deformations (>80% PCE retention under an 80% strain) were demonstrated. Analysis of several SMA-polymer blends revealed general molecular structure–miscibility–stretchability relationships for designing ductile blends.