PbS Quantum Dots/2D Nonlayered CdS _xSe_{1- x} Nanosheet Hybrid Nanostructure for High-Performance Broadband Photodetectors

Two-dimensional (2D) nonlayered nanomaterials have attracted extensive attention for electronic and optoelectronic applications recently because of their distinct properties. In this work, we first employed a facile one-step method to synthesize 2D nonlayered cadmium sulfide selenide (CdS _xSe_{1- x}, x = 0.33) nanosheets with a highly crystalline structure and then we introduced a generic spin-coating approach to fabricate hybrid nanomaterials composed of PbS quantum dots (QDs) and 2D CdS _xSe_{1- x} nanosheets and demonstrated their potential for high-performance broadband photodetectors. Compared with pure 2D CdS _xSe_{1- x} nanosheet photodetectors, the photoelectric performance of the PbS/CdS _xSe_{1- x} hybrid nanostructure is enhanced by 3 orders of magnitude under near-infrared (NIR) light illumination and maintains its performance in the visible (Vis) range. The photodetector exhibits a broadband response range from Vis to NIR with an ultrahigh light-to-dark current ratio (3.45 × 10⁶), a high spectral responsivity (1.45 × 10³ A/W), and high detectivity (1.05 × 10¹⁵ Jones). The proposed QDs/2D nonlayered hybrid nanostructure-based photodetector paves a promising way for next-generation high-performance broadband optoelectronic devices.