Quasi-Two-Dimensional CsPbBr3 Quantum Dot Superlattice/WS2 Hybrid Photodetector: Self-Assembly Fabrication and Performance Optimization

Abstract

The field of optoelectronics has witnessed a surge of interest in hybrid structures that combine colloidal quantum dots (QDs) and two-dimensional (2D) materials. These structures are expected to offer a synergistic blend of high responsivity and rapid response times. However, the potential of QD-based photodetectors has been consistently undermined by the limited carrier mobility in QD films, which arises from the inherent disordered QD and ligand packing produced through conventional fabrication methods. It introduces a pioneering approach to address this limitation: the successful growth and lossless transfer of a micrometer-scale mesocrystalline, oriented packed CsPbBr₃ QD superlattice (SL) onto 2D WS₂. The effective coupling within these SLs endows them with quasi-2D material characteristics and, when integrated with the intrinsic 2D properties of WS₂, results in a photodetector with exceptional performance. Under 405 nm illumination, it demonstrates a remarkable responsivity of 91.24 A/W, a specific detectivity of 1.15 × 10¹¹ Jones, and swift response times of 160 μs/380 μs. These performance metrics exceed those of disordered CsPbBr₃ QDs/WS₂ photodetector prepared by spin-coating, underscoring the superior optoelectronic properties of the SL/WS₂ hybrid structure. This breakthrough not only contributes to the design of high-performance photodetectors but also facilitates transformative progress in the field of optoelectronic technologies.