Self-driven visible-near infrared photodetector with vertical CsPbBr₃/PbS quantum dots heterojunction structure

Self-driven photodetectors are widely used in communication and imaging. As a newly developed semiconductor material, perovskite quantum dots (QDs) are not only bandgap tunable, but also easily combined with other materials. In this paper, a vertical structure self-driven photodetector based on heterojunction of CsPbBr₃ QDs and PbS QDs is proposed, and the device is prepared by solution spin coating method. The device can work in visible and near infrared (400-1130 nm) regions, and has excellent performance, such as ultrafast response speed (rise and decay time are 0.4 μs/0.73 μs under 532 nm laser irradiation in self-driven mode, the estimated response time under 1064 nm laser irradiation is about 11.5 μs), more than 100 dB linear dynamic range for both visible and infrared regions, and good stability. Similarly, the responsivity of the photodetector can also reach an average of 10 mA W^-1, and the detectivity is 1.13 × 10¹⁰ Jones at 0 V bias for 1064 nm laser irradiation. The device combines two kinds of QDs revealing its good prospects and great advantages in self-driven photodetectors and high-speed optical communication devices.