Ultralow Dark Current and High On-off Ratio of Perovskite Photodetectors Enabled by 3D/2D/3D Heterostructures Unipolar Barrier

Lead halide perovskite photodetectors exhibit outstanding photoelectric performance in multiple parameters and have become a widely studied hotspot. The perovskite with single crystal structures significantly reduces the density of grain boundaries and defect states, thereby improving the carrier lifetime and mobility. However, the suppression of dark current is one of the most important concerns for the research of perovskite photodetectors. Here, we constructed a pBp unipolar barrier photodetector by inserting two-dimensional perovskite into three-dimensional perovskite through a pressure bonding process. The dark current of the photodetector decreased by more than two orders of magnitude, while the photocurrent remained unchanged. The perovskite unipolar barrier photodetectors exhibit excellent photoelectric performance, with an on-off ratio of 10(6), a specific detectivity of 4.11 x 10(12 )Jones, a -3 dB cutoff frequency of 344 kHz, and a linear dynamic range of 160 dB, providing a prospective path for weak light detection.