Synthesis of Mn2+:CsPb (Br1−xClx)3 perovskite quantum dots in an ambient atmosphere: stability analysis and self-powered photodetector applications

Abstract

Metal halide-perovskite-quantum dots (MH-PQDs) have gained wide attention due to their tunable optoelectronic properties and better stability against the ambient environment compared to organometal halide-based PQDs. The stability of the perovskite QDs is of utmost importance, considering their application in light emitting diodes and photodetectors. Herein, we have systematically analyzed the stability of perovskite QDs and have fabricated a photodetector device by using the most stable Mn²⁺:CsPb(Br_1−xCl_x)₃ QDs. The manuscript discusses the synthesis of CsPbBr₃ QDs and manganese (Mn) doped Mn²⁺:CsPb(Br_1−xCl_x)₃ QDs using the ligand-assisted re-precipitation (LARP) technique and have studied the correlation between various dopant concentrations and stability. Different concentrations of Mn²⁺ doping (0.7, 1, 1.5, and 3 mmol of MnCl₂·4H₂O) in CsPb(Br_1−xCl_x)₃ QDs were investigated to study the stability by aging and the optimum concentration of Mn²⁺ that could be doped into CsPb(Br_1−xCl_x)₃ QDs which offered better stability concerning its photoluminescence was found. The optical properties of the synthesized QDs were characterized using UV-Vis absorbance, photoluminescence (PL), and time resolved photoluminescence spectroscopy (TRPL) techniques. The formation of CsPbBr₃ QDs with a size of 25.80 ± 3.69 nm and Mn²⁺:CsPb(Br_1−xCl_x)₃ QDs with a size of 22.65 ± 3.28 nm was confirmed by using the high resolution transmission electron microscopy (HR-TEM) technique. TRPL analysis revealed the d–d emission of the Mn²⁺:CsPb(Br_1−xCl_x)₃ QDs at 600 nm due to Mn²⁺ doping. Furthermore, the self-powered photodetector device was fabricated by using stable 0.7 mmol Mn²⁺-doped CsPb(Br_1−xCl_x)₃ QDs and achieved a quick response, such as a rise time (t_on) of 438 ± 8 ms and fall time (t_off) of 592 ± 11 ms under one sun illumination. This work could be useful in the field of optoelectronics, especially in the study of doped semiconductor QDs.