Strain engineering improves the photovoltaic performance of carbon-based hole-transport-material free CsPbIBr 2 perovskite solar cells.

Alkylamines with different chain lengths including n -butylamine, n -hexylamine, and n -octylamine, are applied to regulate the CsPbIBr 2 perovskite film quality by strain engineering. The status of residual strains is controllably modulated, resulting in improved efficiency and stability of carbon-based hole-transport-material free CsPbIBr 2 perovskite solar cells.