Embedding PbS quantum dots in MAPbCl0.5Br2.5 perovskite single crystal for near‐infrared detection

Abstract Organometal lead‐halide perovskites demonstrate excellent photovoltaic performance in the visible (Vis) region. However, their lack of response in the near‐infrared (NIR) region limits their applications in broadband photodetectors. Here, PbS quantum dots (QDs) were successfully embedded in MAPbCl 0.5 Br 2.5 single crystal by solution‐processed epitaxial growth. Perovskites can effectively act as efficient charge transporters. The mobility of MAPbCl 0.5 Br 2.5 with 1 wt% PbS quantum dots crystal is about 85 cm 2 /(V·S), which is similar to that of pure MAPbCl 0.5 Br 2.5 single crystal. Meanwhile, the composite crystal exhibited a broadband response wavelength from the Vis (625 nm) to the NIR (850 nm) with fast response times (τ on /τ off = 6/9 ms and τ on /τ off = 19/43 ms in the Vis and NIR regions, respectively). The photodetector demonstrates a responsivity of 0.02 mA/W with a specific detectivity of 1.2 × 10 8 Jones under 5.1 mW/cm 2 850‐nm illumination at 10‐V bias. These results suggest that we have obtained high‐quality composite crystals with improved photo response in the Vis to NIR region.