溶胶凝胶法制备CdS/SiO2量子点玻璃的研究

通过溶胶凝胶转变过程制备了硫化镉／二氧化硅量子点复合玻璃材料（硫化镉在复合材料中的最大掺杂质量比可达到30％）；并针对两种催化剂对复合体系的不同影响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．TEM法与低频Raman散射法的测定表明实验制备的样品中CdS颗粒基本为nm级的球形粒子。其CdS颗粒粒径随CdS含量增加而增大。随CdS／SiO2量子点玻璃材料中CdS颗粒粒径的减小，其吸收光谱中的吸收边界与常规尺寸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．适宜的热处理过程对复合材料中CdS颗粒粒径的减小和量子效应的增强起着有利的作用．

Study on CdS/SiO_2 Quantum-dot-glass Prepared by Sol-gel Method

The sol-gel process has been applied to the preparation of small size CdS crystal doped silica glasses. Silica glasses containing 0.88 ~30 wt % CdS were synthesized in a process which includes two-step hydrolysis of Si(OC2H5)4 and Cd(CH3COO)2 2H2O,drying and heating of doped gels, and reaction by exposing the porons glass of CdO/SoO2 to H2S gas. The sol-gel transition Point. was determined by measuring the variation of the viscosity with hydrolysis time. It was found that the gel point was affected by the Cd(CH3COO)2. 2H2O content and kinds of acid-catalyst (HNO3 of HCl) .About 2 cm diameter monoliicth dry gel was obtained in the sealed box in which microenvironment(humidity, temperature and chemical atmosphere etc. ) was automaticall controlled by the computer. From the rexults of the low frequency inelastic Ranman scattering and transmission electron micrographs, CdS crystals were 1.6to 804 nm in diameter for different doped systems. in the optical absorption spectra, the absorption edge exhibited a blue shift compared with that of the bulk CdS. Thus the quantum size effect was found for glasses containing CdS prepared by the sol-gel process.