梯度结构三元合金量子点掺杂玻璃及其荧光增强性能研究

Lead chalcogenide quantum dots (QDs) doped glass is an important potential materials for the applications of near- and mid- infrared luminescence because of their narrow band gap and big Bohr radius. Normaly, we change the QDs size to realize the tunable photoluminescence (PL) wavelength range due to the quantum confinement effects. While the QDs with too big or small size, their stability, size distribution, and PL efficiency were not good. This project proposed engineering the compositions and structure of QDs in glasses to broaden the wavelength range and enhance the efficiency of PL. Current research focus on the preparation of tenary QDs which alloyed by alkali-earth chalcogenide and lead chalcogenide in silicate glasses. The effects of the glass composition, thermal heat treatment, and initial concentrations of semiconductor ions and alkali-earth ions on the structure and formation of alloy QDs with gradient structure were studied. High resolution transmission electron microscope, electron energy loss spectroscopy and high temperature in-situ transmission electron microscope will be employed to clarify the nucleation and growth of these gradient structured quantum dots in glasses. Structural analysis will be combined with optical characterization to evaluate the efficiency of QDs, understand the PL enhancement mechanism。As a result, we will develop a kind of QDs doped glass with high efficiency in the near-/mid-infrared wavelength range.

Ⅳ-Ⅵ族半导体具有禁带窄、激子波尔半径大的特性，使得其量子点掺杂玻璃成为一种很有潜力的近、中红外发光材料。由于量子限域效应，通过改变量子点尺寸即可方便的调节其发光波长范围，但是量子点尺寸过大或过小时，其稳定性、粒径分布和荧光性能都不理想。本项目借鉴化学合成中制备梯度合金量子点拓宽量子点发光波段范围及增强量子点荧光效率的方法，提出在玻璃中调整量子点组成及结构，拟以硅酸盐玻璃为基体，制备一种梯度结构的碱土金属硫族化合物与铅硫族化合物三元合金量子点（Pb-M-X）。研究基础玻璃组成、热处理工艺、半导体离子和碱土金属离子在玻璃中的初始浓度对合金量子点形成与结构的影响规律。利用高分辨透射电镜、电子能量损失谱、高温同位透射电镜等手段研究合金量子点核化、生长及结构演变的过程与机理；微观分析结合光学性能表征，研究梯度结构合金量子点的荧光增强性能、机制，研发高近、中红外荧光效率的量子点。

Ⅳ-Ⅵ族半导体量子点具有禁带窄、激子波尔半径大等优良特性，采用传统熔融-热处理法制备PbSe量子点掺杂玻璃，并通过在PbSe量子点中掺杂碱土金属离子，优化其近、中红外发光性能。本项目主要研究了玻璃基质中三元合金量子点的可控制备；玻璃中量子点先驱物含量、热处理制度、基质玻璃组成对PbSe/Pb1-xSrxSe量子点析出的影响规律；硅酸盐玻璃中IV-VI量子点生长机理；PbSe/Pb1-xSrxSe量子点反斯托克斯荧光、光致暗化等荧光特性及其发光机理。研究表明三元Pb1-xSrxSe量子点对比PbSe量子点表现出更好的抗光致暗化性能，说明Sr2+的引入对量子点表面缺陷进行了有效钝化。最后，通过将量子点掺杂微晶玻璃，讨论了玻璃主要组成析晶与微量组成析出的机理及相互影响关系。本研究为开发高性能近、中红外发光固体材料提供了理论基础。