Enhanced π–π Interactions of Nonfullerene Acceptors by Volatilizable Solid Additives in Efficient Polymer Solar Cells

• DOI: 10.1002/adma.201900477
• Publication Date: 2019-03-25T18:04:57Z
• Authors: Runnan Yu; Huifeng Yao; Zhenyu Chen; Jingmin Xin; Ling Hong; Ye Xu; Yunfei Zu; Wei Ma; Jianhui Hou
• Keywords: 7. Clean energy; 01 natural sciences; 0104 chemical sciences

Abstract Fine‐tuning of the nanoscale morphologies active layers in polymer solar cells (PSCs) through various techniques plays a vital role improving photovoltaic performance. However, for emerging nonfullerene (NF) PSCs, morphology optimization active‐layer films empirically follows methods originally developed fullerene‐based blends and lacks systematic studies. In this work, two solid additives with different volatilities, SA‐4 SA‐7, are applied to investigate their influence on performances NF‐PSCs. Although both effectively promote molecular packing NF acceptors, due higher volatility SA‐4, devices processed exhibit power conversion efficiency 13.5%, than that control devices, SA‐7 poor performances. Through series detailed morphological analyses, it is found volatilization after thermal annealing beneficial self‐assembly while residuals incomplete have negative effect film morphology. The results delineate feasibility applying volatilizable provide deeper insights into working mechanism, establishing guidelines further material design additives.