Flattening Grain-Boundary Grooves for Perovskite Solar Cells with High Optomechanical Reliability.

Hao, Mingwei; Duan, Tianwei; Ma, Zhiwei; Ju, Ming-Gang; Bennett, Joseph A; Liu, Tanghao; Guo, Peijun; Zhou, Yuanyuan · Adv Mater · 2023

basic_science · Level V

Where this comes from

Abstract

Optomechanical reliability has emerged as an important criterion for evaluating the performance and commercialization potential of perovskite solar cells (PSCs) due to the mechanical-property mismatch of metal halide perovskites with other device layer. In this work, grain-boundary grooves, a rarely discussed film microstructural characteristic, are found to impart significant effects on the optomechanical reliability of perovskite-substrate heterointerfaces and thus PSC performance. By pre-burying iso-butylammonium chloride additive in the electron-transport layer (ETL), GB grooves (GBGs) are flattened and an optomechanically reliable perovskite heterointerface that resists photothermal fatigue is created. The improved mechanical integrity of the ETL-perovskite heterointerfaces also benefits the charge transport and chemical stability by facilitating carrier injection and reducing moisture or solvent trapping, respectively. Accordingly, high-performance PSCs which exhibit efficiency retentions of 94.8% under 440 h damp heat test (85% RH and 85 °C), and 93.0% under 2000 h continuous light soaking are achieved.