溶胶-凝胶法制备PbS量子点玻璃的研究

采用溶胶-凝胶法合成了半导体PbS量子点掺杂的Na₂O-B₂O₃-SiO₂玻璃，研究了不同热处理工艺对玻璃结构的影响，利用多种表征手段研究了量子点掺杂玻璃中的微晶结构及其光学性能.孔径分析结果表明随着热处理温度的升高玻璃内部孔径不断减小，最终孔结构几乎完全消失；红外光谱分析表明玻璃网络结构在较低温度下己经形成，随温度的升高不断密实化； X射线光电子能谱证明了玻璃中存在PbS，高分辨透射电镜表征了玻璃基质中掺杂的微晶结构是PbS，统计计算表明，玻璃中微晶的平均粒径尺寸为3.5nm；吸收光谱分析发现，微晶掺杂玻璃的吸收边界较PbS的块体材料发生了明显的蓝移，产生了量子尺寸效应；通过Z扫描技术测得其非线性折射率γ为-2.03×10^-14cm²/GW. 关键词： PbS量子点 半导体 非线性光学效应 溶胶-凝胶法

PbS quantum dot doped glass prepared by sol-gel method

Na₂O-B₂O₃-SiO₂ glasses doped with semiconductor PbS quantum dots were fabricated via a sol-gel routine in this paper. The influence of different heat treatment on microstructure of glass were made, and characterization of the micro-crystals doped in glass matrix were made by varies methods. The result of N₂ adsorption-desorption shows that the diameter of pores in the interior of glass diminishes, with increasing temperature, and the pores totally disappear at last. IR spectra indicate that network structure of glass is form at low temperature, and becomes compact at higher temperature. The PbS crystals are found in the glass matrix by both X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM), and the average size of the crystallites is 3.5nm in diameter. Comparing with the bulk PbS, the absorption edge in the optical absorption spectra of glass containing PbS quantum dots exhibits a blue shift and shows obvious quantum size effect. The nonlinear refractive index (γ) of the glass doped with PbS micro-crystals was determined by Z-scan technology to be -1.6×10^-11cm²/GW.