Interfacial Engineering of In 2 Se 3 /h-BN/CsPb(Br/I) 3 Heterostructure Photodetector and Its Application in Automatic Obstacle Avoidance System.

Driven by the rapid development of autonomous vehicles, ultrasensitive photodetectors with high signal-to-noise ratio and ultraweak light detection capability are urgently needed. Due to its intriguing attributes, the emerging van der Waals material, indium selenide (In 2 Se 3 ), has attracted extensive attention as an ultrasensitive photoactive material. However, the lack of an effective photoconductive gain mechanism in individual In 2 Se 3 inhibits its further application. Herein, we propose a heterostructure photodetector consisting of an In 2 Se 3 photoactive channel, a hexagonal boron nitride (h-BN) passivation layer, and a CsPb(Br/I) 3 quantum dot gain layer. This device manifests a signal-to-noise ratio of 2 × 10 6 with responsivity of 2994 A/W and detectivity of 4.3 × 10 14 Jones. Especially, it enables the detection of weak light as low as 0.03 μW/cm 2 . These performance characteristics are ascribed to the interfacial engineering. In 2 Se 3 and CsPb(Br/I) 3 with type-II band alignment promote the separation of photocarriers, while h-BN passivates the impurities on CsPb(Br/I) 3 and promises a high-quality carrier transport interface. Furthermore, this device is successfully integrated into an automatic obstacle avoidance system, demonstrating promising application prospects in autonomous vehicles.