Nanochannel-Assisted Perovskite Nanowires: From Growth Mechanisms to Photodetector Applications

Growing interest in hybrid organic–inorganic lead halide perovskites has led to the development of various perovskite nanowires (NWs), which have potential use in a wide range of applications, including lasers, photodetectors, and light-emitting diodes (LEDs). However, existing nanofabrication approaches lack the ability to control the number, location, orientation, and properties of perovskite NWs. Their growth mechanism also remains elusive. Here, we demonstrate a micro/nanofluidic fabrication technique (MNFFT) enabling both precise control and <i>in situ</i> monitoring of the growth of perovskite NWs. The initial nucleation point and subsequent growth path of a methylammonium lead iodide–dimethylformamide (MAPbI₃·DMF) NW array can be guided by a nanochannel. <i>In situ</i> UV–vis absorption spectra are measured in real time, permitting the study of the growth mechanism of the DMF-mediated crystallization of MAPbI₃. As an example of an application of the MNFFT, we demonstrate a highly sensitive MAPbI₃-NW-based photodetector on both solid and flexible substrates, showing the potential of the MNFFT for low-cost, large-scale, highly efficient, and flexible optoelectronic applications