Layered‐Perovskite Nanowires with Long‐Range Orientational Order for Ultrasensitive Photodetectors

Abstract 2D layered metal‐halide perovskites combine efficient exciton radiative recombination in crystal interior with long‐distance free‐carrier conduction at layer edges, which are promising candidates for realizing high‐performance photovoltaic, light‐emission and photodetection devices. The anisotropic electrical conductivity in layered perovskites imposes an additional requirement of orientational control for enabling favorable charge transport. However, rational fabrication of single‐crystalline nanostructures with pure crystallographic orientation is still elusive. Herein, large‐scale pure (101)‐orientated 2D‐perovskite single‐crystalline nanowire arrays are realized by combining solvent engineering with the capillary‐bridge lithography technique. Ordered nucleation at liquid–air interface and unidirectional growth along the dewetting direction are demonstrated by fluorescence microscopy and grazing‐incidence X‐ray scattering in discrete capillary bridges. In consideration of crystal interior exhibiting high resistance arising from the serial insulating organic barriers and ultrafast dissociation of excitons to generate long‐lived free carriers at layer edges, ultrasensitive photodetectors are demonstrated with average responsivity exceeding 1.1 × 10⁴ A W⁻¹ and detectivity exceeding 9.1 × 10¹⁵ Jones.