Solvent-Assisted Thermal-Pressure Strategy for Constructing High-Quality CH 3 NH 3 PbI 3- x Cl x Films as High-Performance Perovskite Photodetectors.

High-quality CH ₃ NH ₃ PbI _3-x Cl _x films have attracted research interests in photoelectric devices because of their improved carrier diffusion length and charge mobility. Herein, a solvent-assisted thermal-pressure strategy is developed to promote the secondary growth of perovskite grains in the films. Highly oriented perovskite films are then obtained with large-sized grains (5-10 μm). As a consequence, the photodetectors based on the high-quality CH ₃ NH ₃ PbI _{3- x} Cl _x films exhibit enhanced ophtoelectrical performance, including high on/off ratio (>2.1 × 10 ⁴ ), fast response time (54/63 μs), and high detectivity (∼1.3 × 10 ¹² ). This work suggests an effective approach for high-quality perovskite films, which will be promising candidates for other high-efficiency photoelectric devices.