Inhibited cracks development by compressive strain in perovskite solar cells with improved mechanical stability.

Metal halide perovskites are promising as next-generation photovoltaic materials, but stability issues are still a huge obstacle to their commercialization. Here, we investigate the formation and evolution of cracks in perovskite films during thermal cycling, which affects their mechanical stability. We employ compressive strain to suppress cracks and delamination in situ formed polymers with low elastic modulus during crystal growth. The resultant devices passed the thermal cycling qualification (IEC61215:2016), retaining 95% of the initial power conversion efficiency (PCE) and compressive strain after 230 cycles. Meanwhile, the p-i-n devices delivered PCEs of 23.91% (0.0805 cm 2 ) and 23.27% (1 cm 2 ). Our findings shed light on strain engineering with respect to their evolution, which enables mechanically stable perovskite solar cells. This article is protected by copyright. All rights reserved.