The visible light-triggered nonvolatile memory performances in melamine-decorated -oriented lead halide perovskites: A photo-responsive structural evolution insight

Abstract

The exploration of novel photo/thermal-responsive nonvolatile memorizers will be beneficial for energy-saving memories. Herein, new <110>-oriented perovskites using single template melamine, i.e., [(MLAI-H2)(PbX4)]n (X = Br (α-1), Cl (α-2), MLAI = melamine) have been prepared and their structures upon irradiation of visible light have been investigated. They have been fabricated as nonvolatile memory devices with structures of ITO/[(MLAI-H2)(PbX4)]n/PMMA/Ag (device-1: X = Br, device-2: X = Cl), which can exhibit unique visible light-triggered binary nonvolatile memory performances. Interestingly, the silent or working status can be monitored by visible chromisms. Furthermore, the light-triggered binary resistive switching mechanisms of these ITO/[(MLAI-H2)(PbX4)]n/PMMA/Ag memory devices have been clarified in terms of EPR, fluorescence, and single-crystal structural analysis. The presence of light-activated traps in <110>-oriented [(MLAI-H2)(PbX4)]n perovskites are dominated in the appearance of light-triggered resistive switching behaviors, based on which the inverted internal electrical fields can be established. According to the structural analysis, the more distorted PbX6 octahedra, higher corrugated <110>-oriented perovskite sheets, and more condensed organic-inorganic packing in Br-containing perovskite are beneficial for the stabilization of light-activated traps, which lead to the better resistive switching behavior of device-1. This work can pave a new avenue for the establishment of novel energy-saving nonvolatile memorizers used in aerospace or military industries.