Lattice-matched quantum-dots-perovskite solid-sol for the ultrafast, ultrasensitive and ultrastable uncooled photoconductive near-infrared sensor with simple structure

Abstract

Photoconductive near-infrared sensors have the advantages of low cost and simple structure, but their overall performances are dissatisfactory yet. As potential candidates for active layers of near-infrared sensors, lead sulfide quantum dots are often accompanied by the long chain ligands with negative effects. To address this issue, a precursor ink for a lattice-matched methylammonium lead iodide solid sol of lead sulfide quantum dots (PbS-QDs/MAPbI3 solid sol) is developed, which is based on ligand exchange. Subsequently, a high-performance uncooled photoconductive near-infrared sensor based on the PbS-QDs/MAPbI3 solid sol is fabricated by simple dip coating. Outstanding overall performance of this near-infrared sensor on sensing near-infrared light is reflected in the external quantum efficiency over 2458%, the responsivity up to 18.61 A/W, the normalized detectivity up to 1.29 × 1013 Jones, the rise (or fall) time constant less than 2 μs, the ratio of light current to dark current up to 433, the strong linear correlation with 99.8% variance between light current and irradiation intensity, and the 97% retention rate of response within 60 days. The solution-processed uncooled photoconductive near-infrared sensor successfully combines simple structure with outstanding performance.