Bandgap Engineering of Single‐Crystalline Perovskite Arrays for High‐Performance Photodetectors

Abstract Bandgap engineering of single‐crystal lead halide perovskites with remarkable optoelectronic properties, solution processability, and low‐cost nature has been in the forefront of extensive optoelectronic applications. Yet one imminent challenging is to pattern micro‐ and nanostructured perovskite arrays with controlled morphology, precision alignment, and high‐quality single crystallinity owing to the difference of crystallization behaviors between perovskites with diverse halide stoichiometry, leading to the restricted integration of optoelectronic devices. Herein, a facile assembly solution process is developed through cautious regulation, directional dewetting, and microstructured confinement for the nucleation and growth of 1D perovskite single‐crystal arrays with engineered bandgap from 1.7 to 3.1 eV by changing halogen ratios. Photodetectors based on 1D arrays perform a high responsivity of 3.16 × 10 3 A W −1 . In comparison with devices based on perovskite thin film, a notable improvement is achieved owing to the elimination of the carrier recombination in the 1D high‐quality crystalline arrays with the low defect density and long carrier lifetime. This work offers a new insight for the bandgap engineering of patterned single crystals toward the integration of optoelectronic devices.