Self-Assembled Growth of Ultrastable CH₃NH₃PbBr₃ Perovskite Milliwires for Photodetectors

The unstability of organolead halide perovskite under continuous illumination, moisture, and high temperature has seriously impeded its commercial development for long-period applications. Here, a facile method was developed to grow ultrastable CH3NH3PbBr3 milliwires through the reaction of self-assembled PbBr2 milliwire with CH3NH3Br at room temperature. The initial self-assembled PbBr2 milliwire is that PbBr2 complexed with dimethylformamide (DMF) molecular self-assemble into perovskite-type PbBr2. Crystal conversion from PbBr2 to CH3NH3PbBr3 milliwire occurred in the molecular exchange between CH3NH3Br and DMF. The synthesized CH3NH3PbBr3 milliwires present high stability under high humidity ∼75%, continuous illumination, heating, and sustain ultrastability in air for more than 255 days. In addition, the CH3NH3PbBr3 milliwire can be dynamically degraded and reconstructed in the presence of water molecules. The milliwires have strong band-edge photoluminescence (PL) with PL lifetime of ∼110 ns. On the basis of the mono-milliwire-constructed photodetector, it exhibits high photoresponse and fast response time of 0.407 s.