High-Performance Self-Driven MAPbI3-MAPbBr3 Perovskite Single Crystal Heterojunction Photodetectors for Ultra-Sensitive Weak Light Imaging

The rapid advancement of optoelectronic devices, particularly photodetectors, demands enhanced sensitivity for detecting weak light. In this study, MAPbI₃-MAPbBr₃ perovskite single crystal heterojunctions (SCHs) are fabricated via atomic force bonding using liquid-phase epitaxy, with polydimethylsiloxane (PDMS) serving as a substrate protector. The resulting SCHs photodetector exhibits self-driven operation, an ultra-low dark current, and a high on-off ratio of 5.8 × 10⁴ at 0 V bias. Under weak illumination and 5 V bias, the device achieves a maximum external quantum efficiency of 414.9%. With a remarkable detection rate of 4.5 × 10¹³ Jones, the device demonstrates outstanding potential for weak light imaging. Furthermore, the self-driven SCHs photodetector enables high-quality imaging under a 445 nm light source at a remarkably low intensity of 2.7 µW cm⁻², without the need for any external power supply.