二氧化钛纳米晶的制备及其光致发光的研究

以Ti（SO4）2为前驱体，采用沉淀法制备了二氧化钛纳米晶，通过X射线衍射（XRD）、透射电子显微镜（TEM）和光致发光（PL）光谱对微晶进行表征。研究表明，制备的TiO2纳米晶呈类球形颗粒且分散性好，平均粒径最小约为4nm，热处理温度升高到750℃时，样品仍为单一的锐钛矿相；PL谱分析表明，室温下，用高于带隙的能量激发，在370～550nm范围内纳米TiO2粒子呈现出强而宽的发光带，分别对应于价带和导带间的电子跃迁以及表面态的发光；另外发现随焙烧温度升高，粒径增大的同时，发光峰的强度呈无规则变化，分析可能与表面态和晶粒内部缺陷的数量有关。

The preparation and photoluminescence study of titania nanocrystals

Titania nanocrystals were prepared by precipitation method with Ti (SO4)2 as precursor and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and Photoluminescence (PL) spectra. The results indicate that the obtained TiO2 nanocrystals are spherical, well dispersed, and the minimum of average particle diameter is around 4nm. The powder remains anatase phase when the calcining temperature rises up to 750℃. The PL spectra show that the TiO2 nanocrystals display a strong and wide luminescence band in the range from 370～550nm when the excited energy is higher than band gap in the room temperature, and the different luminescence peaks are attributed to the electron transitions between bands and the surface states respectively. Besides, the intensity of luminescence peaks presents irregular changes with increasing grain size, i. e. ,with heat treatment. It may be related to the number of defects inside the grains and surface states which are correlated with heat-treatment.