Embedding PbS quantum dots in MAPbCl_0.5Br_2.5 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 MAPbCl0.5Br2.5 single crystal by solution‐processed epitaxial growth. Perovskites can effectively act as efficient charge transporters. The mobility of MAPbCl0.5Br2.5 with 1 wt% PbS quantum dots crystal is about 85 cm2/(V·S), which is similar to that of pure MAPbCl0.5Br2.5 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 (τon/τoff = 6/9 ms and τon/τoff = 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 × 108 Jones under 5.1 mW/cm2 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.

Perovskite single crystals: physical properties and optoelectronic applications

“…Under 905 nm NIR light irradiation, the as-fabricated detectors achieved a responsivity of 0.514 AW −1 and a specific detectivity of 1.4974 × 10 11 Jones. In addition to Sn doping, adding lead sulfide quantum dots to an MA-based single crystal enabled the extension of the photoresponse range [74,170]. At 850 nm illumination and 10 V bias, the IR photodetectors' responsivity and detectivity reached 0.02 mA W −1 and 1.2 × 10 8 Jones, respectively.…”

“…Hence, all inorganic CsPbBr 3 can be used to construct Vis-IR dual-modal photodetectors and achieve a light on/off ratio of 500 under 800 nm laser excitation (figure 15(c)). Table 8 summaries the performance of IR photodetectors in past years [73,74,[168][169][170][171]. There have been significant improvements in the performance, but for IR photodetectors, thermal stability remains a long-term challenge.…”

Antisolvent-Treated MAPbI3 and PbS Quantum Dots for High-Performance Broadband Photodetectors

“…PbS quantum dots (QDs) has been a standout candidate for infrared photosensitivity due to their high quantum efficiency and tunable band gap (0.6–1.6 eV). − Liu et al constructed a vertically stacked structure for ITO/PEDOT:PSS/PbS QDs/MAPbI 3 /PC 61 BM/Ag, achieving spectral detection from 375 to 1100 nm. It is worth emphasizing that MAPbI 3 acts as both a visible light-sensitive layer and a passivation layer for PbS QDs, resulting in devices with detection rates of 10 13 and 5 × 10 12 Jones in the VIS and NIR regions, respectively .…”