Highly Sensitive CuInS₂/ZnS Core-Shell Quantum Dot Photodetectors

QD-based high-performance photodetectors (PDs) typically contain hazardous elements such as lead- and cadmium-based materials, raising toxicity and safety concerns for optoelectronic devices. Here, we demonstrate solution-processed sandwich-structured PDs based on environmentally benign CuInS2/ZnS core-shell quantum dots (QDs) layer stacked with organic blend film of the hole transport material and electron transport material. Owing to an effective energy transfer from the photoexcited QDs to the adjacent organic blend films, charge separation and fast charge transport are significantly enhanced. Due to the unique heterojunction architecture, the dark current is substantially suppressed with the applied gate bias. The obtained PDs have a low dark current, a high detectivity of 3.8 × 1011 Jones, and a fast response time (<5 ms). The detailed experimental investigation elucidates the critical aspects of the PDs. This work shows a feasible strategy to develop highly sensitive PDs from heavy-metal-free core-shell QDs.