卤化物双钙钛矿纳米晶表面钝化及发光增强研究

具有优异光电性质的卤化铅钙钛矿(APbX3)材料是一种极具应用潜力的半导体材料，但铅毒和稳定性问题限制其商业化应用。近期非铅钙钛矿的研究虽然能解决铅毒和一定的稳定性问题，但其光学性能与APbX3相比还有很大的差距。本项目拟以卤化物双钙钛矿纳米晶(DPNCs)(Cs2AgBiX6，Cs2AgSbX6, Cs2AgInX6, Cs2SnX6) (X=Cl，Br，I)作为研究模型，针对目前DPNCs光学性能差、表面缺陷态及表面钝化机理不清晰等科学问题，采用配体钝化DPNCs表面缺陷、调控形貌和大小进而提高发光性能的思路。通过制备不同表面配体钝化DPNCs的研究，揭示表面钝化因素对DPNCs发光性能的影响，建立DPNCs表面钝化提高发光性能的一般性方法。探讨DPNCs生长机理和发光机理。DPNCs形成自组装超晶体的条件。本研究将为提高DPNCs发光性能和稳定性等科学问题奠定实验和理论基础。

Lead halide perovskites are among the most promising materials in optoelectronic applications, which has drawn tremendous attention due to their excellent photoelectrical properties, such as high absorption coefficient, tunable bandgap and long carrier diffusion length. However, several issues, such as the toxicity of lead and instability, still remain as obstacles to their practical applications. In this project, halide Double- Perovskite Nanocrystals (DPNCs,(Cs2AgBiX6，Cs2AgSbX6, Cs2AgInX6, Cs2SnX6) (X=Cl，Br，I) ) will be investigated as a model system to understand the origin of instability and mechanism of surface passivation as a means to improve their stability and optical properties. Specifically, DPNCs with different compositions and surface ligands will be prepared by introducing substitutive precursors and effective capping ligands. The surface properties of DPNCs including defects and surface composition will be systematically studied. We seek to demonstrate several strategies for highly effective surface passivation. The growth mechanism and luminescence mechanism of DPNCs will also be investigated, along with self-assembled supercrystals of DPNCs that have unique properties for different potential applications. This project will provide an experimental and theoretical foundation for effectively passivating surface defects of DPNCs and improving their optical properties and stability critical for emerging nanotechnologies.