A 2D Perovskite Photodetector for NIR Range and Weak-Light Imaging Applications via Thermal Regulation

2D halide perovskites have attracted significant attention in photodetectors due to their inherent stability and outstanding optoelectronic properties. Owing to strong quantum confinement effects in low-n phases (n < 5), pure Pb-based 2D perovskites typically exhibit large bandgaps (> 1.6 eV), limiting their photodetection to the ultraviolet–visible region and leading to insufficient near-infrared (NIR) response. In the present work, the 2D PEA₂FA₄Pb₅I₁₆ perovskite with superior crystallinity, a thicker perovskite absorption layer, and suppressed n = 2 phase presence, is fabricated via a thermal regulation method, enabling the development of a self-power, high-sensitivity NIR photodetector. The 2D perovskite photodetector exhibits excellent operational characteristics, including an extremely low noise current of less than 3 pA Hz^−1/2, and a high on/off switching ratio of up to 2 × 10⁵. A notable responsivity of 0.325 A W⁻¹ at 800 nm is achieved. Consequently, the 2D perovskite photodetector is capable of successfully acquiring high-resolution images under weak NIR illumination (0.1 µW cm⁻²). These findings accentuate the tremendous potential of 2D perovskites in NIR weak light imaging, such as autonomous driving, machine vision, medical diagnostics, and other emerging fields.