2D Ruddlesden‐Popper Sn‐Based Perovskite Weak Light Detector for Image Transmission and Reflection Imaging

Abstract 2D Ruddlesden‐Popper Sn‐based perovskite has excellent optoelectronic properties and weak halide ion migration characteristics, making it an ideal candidate for weak light detection, which has great potential in light communication, and medical applications. Although Sn‐based perovskite photodetectors are developed, weak light detection is not demonstrated yet. Herein, a high‐performance self‐powered photodetector with the capability to detect ultra‐weak light signals is designed based on vertical PEA 2 SnI 4 /Si nanowires heterojunction. Due to the low dark current and high light absorption efficiency, the devices present a remarkable responsivity of 42.4 mA W −1 , a high detectivity of 8 × 10 11 Jones, and an ultralow noise current of 2.47 × 10 −13 A Hz −1/2 . Especially, the device exhibits a high on–off current ratio of 18.6 at light signals as low as 4.60 nW cm −2 , revealing the capacity to detect ultra‐weak light. The device is applied as a signal receiver and realized image transmission in light communication system. Moreover, high‐resolution reflection imaging and multispectral imaging are obtained using the device as the sensor in the imaging system. These results reveal that 2D PEA 2 SnI 4 ‐based self‐powered photodetectors with low‐noise current possess enormous potential in future weak light detection.