Type-i heterostructure and improved phase stability of formamidinium lead iodide perovskite grown on WS2

Abstract

Heterostructures of two-dimensional materials provide an opportunity for the discovery of novel properties and improved material performances. In this work, we demonstrate the chemical vapor deposition growth of two-dimensional perovskite/WS2 heterostructures. Owing to type-I band alignment, photoluminescence (PL) measurements indicated the photogenerated carrier transfer from the WS2 to the perovskite layer. In order to investigate the carrier transfer mechanism, power-dependent PL spectra were measured. The PL intensity of the two-dimensional perovskite grown on WS2 exhibited super-linear dependence to the excitation power. In addition, twodimensional perovskites grown on WS2 showed better air stability compared with the pristine perovskite. The improved stability is attributed to strain in the two-dimensional perovskite layer induced by the underlying WS2. The results presented here offer better understanding of the twodimensional perovskite based heterostructures and their potential use in practical applications, such as light emitting diodes and lasers.