Research on photodetdctors based on zinc-doped tin-lead perovskite quantum dots

The problems of Sn^2+ being easily oxidized and the limited water-oxygen stability of Sn^2+-doped CsPbBr_2I quantum dots (QDs) have hindered the further advancement of optoelectronic devices based on these materials, representing a key challenge in the field. In this study, we employed a double-doping strategy to prepare Sn-Zn:CsPbBr_2I QDs. The incorporation of Zn^2+ effectively contracts the crystal lattice and blocks oxygen diffusion pathways, thereby suppressing the oxidation of Sn^2+, which was confirmed by x-ray diffraction testing. Furthermore, the introduction of Zn^2+ enhances the optical performance of the QDs. At an optimal Pb/Sn/Zn molar ratio of 0.85/0.10/0.05, the photoluminescence intensity increased by 78% compared with that of CsPbBr_2I QDs. Additionally, the photodetector fabricated with Sn-Zn:CsPbBr_2I QDs exhibited a responsivity of 0.44 A/W and a specific detectivity of 1.42 \times10^13 Jones, outperforming the CsPbBr_2I QD-based device (0.38 A/W and 6.07\times10^12 Jones). This work offers a new approach to enhancing the stability of Sn:CsPbBr_2I QDs and supports the development of low-toxicity and high-performance optoelectronic devices.