非铅钙钛矿纳米晶复合玻璃的制备和性能研究

Due to the excellent optical performance, all-inorganic perovskite nanocrystals exhibit great application prospects in illumination, display, biological imaging and other fields. However, the water- and thermal instability of the inorganic perovskite nanocrystals as well as the environmental unfriendliness of lead-based (CsPbX3, X=Cl, Br, I) nanocrystals limit their applications. This project plans to select a stable low-melting glass system (borosilicate, phosphosilicate, or tellurium silicate glass, etc.) as matrix and choose lead-free perovskite nanocrystals (Sn-, Sb-, or Bi-based) as research objects. The glass will be prepared by melt quenching and then heat-treated to precipitate nanocrystals inside the glass matrix in situ. By studying the growth kinetics of lead-free perovskite nanocrystals in glass, the growth mechanism will be revealed and the controllable preparation of lead-free perovskite nanocrystal composite glass will be realized. The defects characteristics on the boundaries between the nanocrystals and glass matrix will be deeply studied as well. Through following passivation of nanocrystal-glass interface defects and element doping, it aims to optimize the fluorescence efficiency. The stability of lead-free perovskite nanocrystal composite glass under laser irradiation and in water, air or other environments will be characterized. It is expected to achieve lead-free inorganic perovskite nanocrystals composite glass with high stability and luminescence efficiency >80%. Consequently, this project will be very helpful to developing highly efficient, stable and environmentally friendly perovskite luminescent materials, which will provide new idea and technical support for the development of new functional optical materials and devices.

全无机钙钛矿纳米晶具有优异的光学性能，在照明、显示和生物成像等领域有着巨大的应用前景。针对铅基钙钛矿纳米晶（CsPbX3，X=Cl、Br、I）的环境不友好性和水、热不稳定性，本项目拟选择稳定的低熔点玻璃体系（硼硅酸盐、磷硅酸盐、碲硅酸盐玻璃等）为基质，以非铅钙钛矿纳米晶（Sn基、Sb基、Bi基）为研究对象，通过熔融淬冷法制备玻璃，后进行热处理在玻璃中原位析出纳米晶。通过研究非铅钙钛矿纳米晶在玻璃中的生长动力学，揭示其在玻璃中的生长机理，实现非铅钙钛矿纳米晶复合玻璃的可控制备；深入研究纳米晶-玻璃界面的缺陷性质，通过界面缺陷钝化和元素掺杂优化其荧光量子效率；表征非铅钙钛矿纳米晶复合玻璃在激光辐照下和水、空气等环境中的稳定性，获得具有高稳定性且荧光量子效率>80%的非铅钙钛矿纳米晶复合玻璃。本项目旨在发展高效、稳定且环境友好的钙钛矿发光材料，为开发新型照明显示材料和器件提供新思路和技术支撑。

全无机钙钛矿具有优异的光学性能，在照明、显示和生物成像等领域有着巨大的应用前景，但目前研究较多的铅基钙钛矿具有环境不友好性，且光学性能优异的钙钛矿纳米晶具有水、热不稳定性，难以实现实际应用。本项目系统探索了非铅基钙钛矿衍生物A3B2X9(其中A可以是K+，Rb+，Cs+，B可以是Sb3+，Bi3+，X可以是Cl-，Br-和I-)，针对A3B2X9的结构与A位和X位元素构效关系不清晰的问题，计算了A3B2X9的容差因子t和八面体因子u，定量提出了A3B2X9型钙钛矿的结构判据，筛选出了具有稳定结构的非铅钙钛矿，并通过第一性原理理论计算了结构参数、电子能带等；筛选出了稳定的低熔点玻璃体系（硼硅酸盐、磷硅酸盐、碲硅酸盐玻璃等）为基质，通过熔融淬冷法制备玻璃，后进行热处理在玻璃中原位析出纳米晶。通过研究钙钛矿纳米晶在玻璃中的生长动力学，揭示了其在玻璃中的生长机理，实现了钙钛矿纳米晶复合玻璃的可控制备；深入研究了纳米晶-玻璃界面的缺陷性质，通过在纳米晶表面形成与之晶体结构相似的无机钝化层实现了界面缺陷钝化，将荧光量子效率提高到70%以上；研究了介电限域和激子限域的调控机理，有效提高了纳米晶的辐射复合速率，将纳米晶复合玻璃的寿命降低至10 ns以内，实现了复合玻璃光学性能的有效优化；应用探索方面，研究了钙钛矿纳米晶复合玻璃的激光损伤阈值、光致变亮及光致变暗机理、高温、潮湿、酸碱环境下的发光退化机理，实现了钙钛矿纳米晶复合玻璃在LED，水下光通信和闪烁体领域应用的原型器件，并获得了良好的器件性能和稳定性，为开发新型发光材料和器件提供了新思路和技术支撑。