低温水热法制备ZnS:Co+Cr纳米晶及其光学性能研究

采用低温水热法制备出3-巯基丙酸(MPA)修饰的ZnS:Co+Cr纳米晶. 利用X射线衍射仪、粒度分析仪、透射电镜、紫外-可见分光光度计、荧光分光光度计和XPS能谱仪等对ZnS:Co+Cr纳米晶的结构、形貌、粒径分布和发光性能进行了表征. 结果表明: 合成的ZnS:Co+Cr纳米晶有较好的单分散性, 平均粒径为9.3 nm, 均为立方闪锌矿结构; ZnS:Co+Cr纳米晶的吸收边位于320 nm处, 并在728 nm处出现Co²⁺的特征吸收峰; 当Cr²⁺浓度为0.75at%, 水热反应温度为160℃时, ZnS:Co+Cr纳米晶PL峰最强; XPS能谱表明Cr²⁺部分被氧化成Cr³⁺。

Optical Properties of ZnS:Co+Cr Nanocrystals Synthesized by a Low Temperature Hydrothermal Process

Water-soluble ZnS:Co+Cr nanocrystals (NCs) were synthesized by a low temperature hydrothermal process using 3-mercaptopropionic acid (MPA) as capping agent. X-ray diffraction, laser particle size analyzer, transmission electron microscope (TEM), UV-Vis spectrophotometer, fluorescence spectrophotometer, XPS were used to characterized crystalline structure, morphology, particle size and optical properties of the samples. It is found that the ZnS:Co+Cr NCs are monodisperse and show zinc blende structure with an average particle size of about 9.3 nm. The absorption edge of ZnS:Co+Cr NCs is observed at 320 nm from the UV-Vis absorption spectra, furthermore the characteristic absorption peak at 728 nm of Co²⁺ is observed. The photoluminescence characteristics indicate that ZnS:Co+Cr NCs shows the maximum PL intensity value under the condition: Cr-doping concentration of 0.75at% and the hydrothermal reaction temperature of 160℃. As confirmed by X-ray photoelectron spectroscope(XPS) , the Cr²⁺ dopants are partialiy oxidized into Cr³⁺.