Fabrication of CsPb_1−x Mn _x Br_3−2x Cl_2x (x = 0–0.5) quantum dots for near UV photodetector application

Abstract In this study, CsPb1–x Mn x Br3–2x Cl2x (x = 0–0.5) nanoparticles were synthesized directly in toluene solvents at high temperature. This approach results in small-size nanoparticles, which can be used in photoelectric components without adding a filtration process to eliminate high-temperature solvents such as octadecene. The high content Mn2+-incorporated CsPb(Cl/Br)3 host is observed by strongly wideband emission at 592 nm of manganese d-states spin and orbital forbidden transition. After infiltration into mesoporous TiO2, the Mn2+ ion receives energy from the CsPb(Cl/Br)3 host (irradiated 405 nm light-emitting diode source) and effectively transfers to the TiO2 scaffold layer. As a result, a metal/semiconductor/metal planar structure photodetector with m-TiO2/CsPb1–x Mn x Br3–2x Cl2x (x = 0–0.5) composite showed several figures of merit compared to bare m-TiO2 and m-TiO2/CsPbBr3 such as on/off ratio of 104 times, responsivity of 1.67 A·W−1, and detectivity of 4.42 × 109 Jones. The key factors contributing to the growth of the on/off ratio include the decreasing dark current and enhancing exciton energy and transportation due to the infiltration of CsPb1–x Mn x Br3–2x Cl2x (x = 0–0.5) perovskite quantum dots into mesopores of the m-TiO2 scaffold layer.