Type-II CsPbBr3/SnS2 heterostructure nanocrystals: toward a high-performance self-powered UV photodetector

Abstract

All-inorganic lead halide perovskite quantum dots (QDs) have emerged as promising materials for photodetection owing to their exceptional optoelectronic properties. However, solution-processed CsPbBr₃ QD films suffer from severe carrier recombination losses and inefficient charge transport. Herein, we address these challenges through rational design of Type-II CsPbBr₃/SnS₂ nanohybrid heterostructures, where SnS₂ nanoparticles serve as electron transport pathways. Systematic characterization reveals that the interfacial energy band alignment enables fast charge separation while suppressing radiative recombination compared to pristine CsPbBr₃ QDs. Based on these advantages of the CsPbBr₃/SnS₂ heterostructure, we demonstrate a self-powered UV photodetector exhibiting high sensitivity with a detectable threshold as low as 0.06 mW cm⁻² at zero bias. The optimized device exhibits a high responsivity of 142.5 mA W⁻¹, a remarkable specific detectivity of 1.13 × 10¹³ Jones, an ultrafast response time of 4 ms and a linear dynamic range of 84.4 dB. The device also exhibits an ultralow dark current in the order of 10⁻¹¹ A, enabling a light-to-dark current ratio of up to 16 522. These parameters surpass those of most previously reported perovskite QD-based photodetectors. This work provides a viable strategy for engineering perovskite heterostructures toward high-performance optoelectronics, particularly for UV monitoring and industrial process control systems requiring zero-power operation.