微波-淀粉辅助合成ZnS纳米晶及其光学性能研究

Microwave and starch-assisted synthesis and optical property of ZnS nanocrystallites

以乙酸锌为锌源,硫代乙酰胺(TAA)为硫源,淀粉为分散剂,微波辅助合成了硫化锌(ZnS)纳米晶。研究了不同微波温度对ZnS结构和晶粒大小的影响,并对形成机理进行了探讨。通过X射线衍射仪(XRD)、透射电子显微镜(TEM)、电子扫描显微镜(SEM)、傅里叶红外光谱(FT-IR)、紫外-可见吸收光谱(UV-Vis)和荧光分光光度计(FL)对物相、形貌、化学键合性质和光学性能等方面,进行了表征分析。结果表明:制得的样品为纯闪锌矿立方相ZnS,晶格常数为0.5196nm;晶粒大小随着温度增加而增大;粒径分布较窄,粒径100~160nm;禁带宽度处为3.85eV,与体相材料的禁带宽度E_g=3.68eV相比,发生了蓝移,可能是量子限域效应和材料形貌所致;所测样品有1个主发射峰和肩峰,处于蓝绿光谱段,归因于表面缺陷和近带边发射。

With zinc acetate as zinc source,thioacetamide（ TAA） as sulfur source and starch as a dispersing agent,ZnS nanocrystallites were prepared via microwave-assisted method. The effect of different microwave temperatures on the structure and crystallite sizes of samples were investigated,and the forming mechanism was discussed. By X-ray diffraction（ XRD）,high resolution transmission electron microscopy（ TEM）,scanning electron microscopy（ SEM）,fourier transform infrared spectroscopy（ FTIR）,ultraviolet-visible spectroscopy（ UV-Vis） and fluorescence spectrophotometer（ FL）,the phase,morphology,chemical and optical properties were characterized. The results showed that the samples were pure zinc blende ZnS with cubic phase and lattice constant of 0. 5196 nm. Crystallite size increased with the increase of temperature. The samples had a narrow particle size distribution with the average particle size of 100 ～ 160 nm. The width of gap band of the sample was 3. 85 eV,and compared to bulk phase material（ Eg= 3. 68 eV）,the blue shift happened,due to the quantum confined effect and material morphologies. The measured sample had a primary emission peak and shoulder peak,in the blue and green spectrum section,caused by the surface defect and the near band edge emission.