溶胶凝胶法制备PbS/SiO2量子点玻璃的研究

经溶胶凝胶转变过程制备了硫化铅/二氧化硅(PbS/SiO₂)量子点复合玻璃材料，利用高分辨透射电镜、可见紫外吸收光谱、比表面分析、热分析等手段对这一类体系的物理化学性质进行了较为系统的研究。复合体系的溶胶凝胶转变点可通过对复合溶胶粘度随时间变化的观测而确定。高分辨电镜观察表明 PbS/SiO₂ 复合材料中PbS颗粒基本为nm级的球形粒子。由于复合材料中纳米级PbS颗粒的存在，其吸收光谱中的吸收边界与常规尺寸PbS颗粒的吸收光谱边界相比有明显的蓝移，体现出显著的量子效应。

Study on PbS/SiO2 Quantum-Dot-Glass Prepared by Sol-Gel Method

The sol-gel process has been applied to preparation of small size PbS crystal doped silica glasses. Silica glasses containing 0.87%-6.6% PbS were synthesized in a process which includes the two-step hydrolysis of Si(OC₂H₅)₄ and Pb(CH₃COO) ₂·3H₂O, drying and heating of doped gels, and the reaction by exposing the porous glass of PbO/SiO₂ to H₂S gas. The sol-gel transition point and specific surface area for the doped system were measured. Surfactant microemusion is added to the Sol-gel process to obtain smaller size PbS microcrystal with narrower size distribution. From the results of transmission electron micrographs, PbS crystals were 3-6nm in diameter for methanol method and 2-3nm for microemulsion method. In the optical absorption spectra, the absorption edge exhibited a blue shift compared with that of the bulk PbS, especially for the samples made by microemusion method. Thus the quantum size effect was found for glasses containing PbS prepared by the sol-gel process.