Self-Assembled Growth of Ultrastable CH 3 NH 3 PbBr 3 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 CH ₃ NH ₃ PbBr ₃ milliwires through the reaction of self-assembled PbBr ₂ milliwire with CH ₃ NH ₃ Br at room temperature. The initial self-assembled PbBr ₂ milliwire is that PbBr ₂ complexed with dimethylformamide (DMF) molecular self-assemble into perovskite-type PbBr ₂ . Crystal conversion from PbBr ₂ to CH ₃ NH ₃ PbBr ₃ milliwire occurred in the molecular exchange between CH ₃ NH ₃ Br and DMF. The synthesized CH ₃ NH ₃ PbBr ₃ milliwires present high stability under high humidity ∼75%, continuous illumination, heating, and sustain ultrastability in air for more than 255 days. In addition, the CH ₃ NH ₃ PbBr ₃ 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.