Freestanding CH3NH3PbBr3 single-crystal microwires for optoelectronic applications synthesized with a predefined lattice framework

Abstract

Metal halide perovskites (MHPs) have shown unparalleled potential for optoelectronic applications. In particular, the quasi one-dimensional perovskite structures have attracted great attention due to their unique optoelectronic properties which can open up new possibilities for this exciting materials system. However, it is challenging to acquire one-dimensional cubic-phase MHPs in high yield due to their isotropic crystallization nature and instability towards conventional fabrication processes. Here, we demonstrate the feasibility of synthesizing single-crystalline perovskite microwires from an intrinsic 1D structured lattice framework which defines the size and shape of the resulting microwires. By incorporating the appropriate monovalent ions into the lattice of self-assembled PbBr₂ microwires, single-crystal CH₃NH₃PbBr₃ microwires are successfully synthesized. The excellent crystal quality of the microwires has led to a high carrier mobility of 36 cm² V⁻¹ s⁻¹ and a long charge carrier lifetime of ∼100 ns. As a preliminary demonstration of their optoelectronics functionality, single CH₃NH₃PbBr₃ microwire-based photodetectors are fabricated and the devices exhibit a fast response time (a rise time of 113 μs and a decay time of 295 μs), stable light switching behavior, high sensitivity, and good spatial resolution. The method described here proposes a novel and facile strategy for synthesizing single-crystal perovskite microwires with high yield and repeatability, showing the great promise of MHPs in micro-optoelectronic applications.