Stable organic lead iodides with three-dimensional crystallographic and electronic structures showing high photoresponse

Abstract

Motivated by the success of methylammonium lead iodide, substantial efforts have been made to search for moisture- and air-stable metal halide perovskites (MHPs) for various optoelectronic applications. Lowering the structural dimensionality in 2D and quasi-2D MHPs greatly increases the stability, but the simultaneously lowered electronic dimensionality leads to less efficient and large anisotropic charge carrier separation and transport. Herein, we report the construction and characterization of three 3D MHP analogs APb₂I₆ (A = linear alkyl-diammonium cation) displaying balanced high stability and isotropic photoresponse. Single-crystal-based devices exhibit on/off ratios of photocurrent higher than 1.0 × 10³ in all three crystallographic directions and ultra-long device stability (>12 months) at 40% relative humidity. The enhanced stability and quasi-isotropic photoresponse are ascribed to the specific choice of the cations and the genuine 3D electronic dimensionality. This type of 3D MPH analog is expected to be a promising candidate for fabricating high-performance optoelectronic devices.