Effect of Humidity on Crystal Growth of CuSCN for Perovskite Solar Cell Applications.

Copper(I) thiocyanate (CuSCN) is one of the most robust hole-transport materials for perovskite solar cells (PSCs). However, the power conversion efficiency of CuSCN-based PSCs is low due to difficulty in crystallization of CuSCN. In this study, we focused on humidity conditions during the aging process of CuSCN-based PSCs to improve their performance. PSCs aged in humid air, i. e., at a relative humidity of 70 %, exhibited better performance (efficiency; 10.6 %) than those aged in lower humidity (5.9 %) due to improved crystallinity of CuSCN layers. The results of the study provide insights into how to improve fabrication process of CuSCN-based PSCs for higher stability and efficiency.