Self-template Synthesis of Metal Halide Perovskite Nanotubes as Functional Cavities for Tailored Optoelectronic Devices.

Intriguing optoelectronic features of low-dimensional perovskites drive researchers to develop novel nanostructures for exploring new photophysical properties and meeting the requirements of future practical applications. Here, we report the facile and universal synthesis of metal halide perovskite nanotubes (NTs) in a micro alkylammonium emulsion system for the first time. The [PbBr6]4--based NTs with a diameter of 300 nm and length of 100 μm were synthesized through the reaction of PbBr2 and long-chain bromide in advance, which can be controllably converted into general metal halide perovskite APbBr3 (A = Cs, FA, MA) with preserved tubular morphology by introducing the Cs+, MA+, and FA+ cations. Importantly, the NTs can readily couple with other nanofillers exhibiting tunable and novel optoelectronic properties demonstrated by the photodetectors. The device performance can be significantly improved and broadened to infrared photoresponse through the introduction of Au nanocrystal (NC) plasma and PbS NCs, respectively. These results demonstrate that the metal halide perovskite NTs are expected to enrich the diversity of nanostructures and have a huge potential in the fabrication of integrated, light-manipulated, and miniaturized electronic and photonic devices.