Centimeter‐Scale Growth of Unidirectional CsCu2I3 Wire Arrays for High Performance UV Photodetectors

Abstract Lead‐free CsCu 2 I 3 has attracted tremendous research interests for photonics and photoelectronics due to their nontoxicity, unique electronic structure, and excellent stability. However, it is still challenging to achieve large‐scale ordered arrays of CsCu 2 I 3 micro/nanowires, which limits their functional applications in integrated optoelectronic devices. Herein, unidirectional CsCu 2 I 3 wire arrays are achieved in centimeter scale through a modified microchannel‐assisted spatial confinement strategy, which can confine the precursor solution into the pre‐fabricated microchannel arrays in large area and control its evaporation. The microstructure characterizations reveal that the orthorhombic CsCu 2 I 3 wires are grown along the c ‐axis with high crystallinity. The control experiments and theoretical studies indicate that the initial CsCu 2 I 3 nucleation at the front of the solution in the channels and the stable solute supply maintained by the movement of the coverslip determine the growth of the wires. The photodetectors based on the CsCu 2 I 3 wires show a high responsivity (80 mA W −1 at 365 nm; 1.29 A W −1 at 330 nm) and fast response speed ( t rise / t decay = 640 µs/7.1 ms). Furthermore, these CsCu 2 I 3 wire arrays exhibit great potential in future flexible electronic and UV imaging applications. This work opens a new way to grow well‐aligned copper‐based halides nano/microwire arrays for the integrated optoelectronics applications.