Millimeter-Sized Single-Crystal CsPbrB/CuI Heterojunction for High-Performance Self-Powered Photodetector.

Millimeter-sized CsPbBr single crystals were prepared via a facile solvent-evaporation method in ambient environment. The heterojunction between p-type CuI and n-type CsPbBr was formed by a simple immersion process. The as-integrated CsPbBr/CuI device exhibits a good rectifying behavior (ratio of 250 at ±2 V). In particular, the photodetector shows excellent self-powered characteristics under 540 nm light illumination, including high photocurrent (near 100 nA); high photosensitivity (on/off ratio of 1.5 × 10); fast response speed (0.04/2.96 ms); and good wavelength selectivity (565-525 nm), responsivity (1.4 mA W), and detectivity (6.2 × 10 Jones). This work provides a simple, low-cost, and effective method for preparing millimeter-level CsPbBr single crystals. The simple device architecture further provides a promising approach for fabricating high-performance self-powered photodetectors.