ZnSe/5B_2O_3-95SiO_2纳米复合材料的制备及性能表征

Preparation and Characterization of ZnSe/5B_2O_3-95SiO_2Nanocomposites

采用溶胶凝胶工艺在室温合成含有Zn、Se成分和玻璃相成分的均匀透明凝胶,并通过CO还原气氛热处理,在凝胶玻璃中原位生长出ZnSe纳米晶体.利用BET比表面积、透射电镜、吸收光谱、荧光光谱等分析手段对ZnSe纳米复合材料的组成结构及量子尺寸效应影响下的光学性能进行了表征,结果表明:5B2O3-95SiO2凝胶玻璃的多孔结构可有效地分散ZnSe纳米晶粒;纳米复合材料中ZnSe纳米晶粒呈球形,粒径约为3.5 nm;吸收光谱中,ZnSe纳米复合材料的吸收边相对于ZnSe体材料发生蓝移,随着ZnSe在凝胶玻璃中摩尔分数的增大,蓝移量减小,相应ZnSe纳米晶粒尺寸增大;在荧光光谱中,500 nm附近的发光带是凝胶玻璃中的ZnSe纳米晶体表面态复合和缺陷发光,当ZnSe的摩尔分数达到0.07时,观测到了浓度的荧光淬灭现象.

Homogeneous and transparent gel glass with Zn,Se elements was prepared in the room temperature by using sol-gel method. ZnSe nanocrystals were grown in-situ in the gel glass by properly annealing process in the CO atmosphere. Components and structures of ZnSe nanocomposites were characterized by BET surface area, X-ray diffraction, transmission electron microscopy, et al. The optical properties of ZnSe/5B2O3-95SiO2 nanocomposites were investigated by UV-vis absorption spectrum and photoluminescence （PL） spectra. As a result, ZnSe nanocrystals could be dispersed effectively in the mesostructure of sol-gel glass, which were shaped like a sphere with about 3.5 nm in diameter. Compared to the ZnSe bulk materials, the absorption edge of the nanocomposites shifted to shorter wavelength in UV-vis spectrum. With increasing ZnSe molar ratio in the nanaocomposites, the magnitude of blue-shift became smaller due to quantum size effect mainly, at the same time, the size of ZnSe nanocrystal became larger. The bands of emission at about 500 nm were originated from recombination of the surface state and defects of ZnSe nanocrystals in the PL spectrum. The fluorescence quenching was observed as ZnSe molar ratio up to 0.07.