给出了裸的及包覆的 Sn O2 纳米微晶的吸收、荧光和激发谱的实验结果。发现随着粒子尺寸的减小 ,包覆一层有机分子的 Sn O2 纳米微晶的吸收谱带边向长波方向发生位移 ,这与裸Sn O2 纳米微晶的结果是不一致。表明纳米晶体的尺寸及其表面状态对它们的光谱性质有很大影响。从量子限域效应和介电限域效应两个方面对实验结果进行了讨论 The experimental results of absorption, fluorescence and excitation spectra of bare and coated Sn O2 nanocrystallites are given. It was found that with the decrease of particle size, the absorption band of the SnO2 nanocrystals coated with a layer of organic molecules shifted in the direction of longwave, which is not consistent with the results of bare SnO2 nanocrystallites. It shows that the size and surface state of nanocrystals have a great influence on their spectral properties. The experimental results are discussed from two aspects: quantum confinement effect and dielectric confinement effect