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

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 × 10³ 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.