低温水热法制备ZnS:Co+Cr纳米晶及其光学性能研究

doi:10.15541/jim20140034

摘要/Abstract

摘要：

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⁺。

关键词: 水热法, ZnS:Co+Cr纳米晶, 物相结构, 光学性能

Abstract:

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⁺.

Key words: hydrothermal synthesis, ZnS:Co+Cr NCs, crystalline structure, optical properties

中图分类号:

O614

王孝笑, 杨琳, 刘洪, 陈强, 肖定全, 朱建国. 低温水热法制备ZnS:Co+Cr纳米晶及其光学性能研究[J]. 无机材料学报, 2014, 29(10): 1049-1054.

WANG Xiao-Xiao, YANG Lin, LIU Hong, CHEN Qiang, XIAO Ding-Quan, ZHU Jian-Guo. Optical Properties of ZnS:Co+Cr Nanocrystals Synthesized by a Low Temperature Hydrothermal Process[J]. Journal of Inorganic Materials, 2014, 29(10): 1049-1054.

图/表 7

图1 ZnS:Co+Cr(0.5at%)纳米晶的粒度分布(a)和TEM形貌(b)

Fig. 1 Particle size distribution (a) and TEM image (b) of ZnS:Co+Cr (0.5at%) nanocrystals

图2 不同掺铬浓度的ZnS:Co+Cr纳米晶的XRD图谱

Fig. 2 XRD patterns of ZnS:Co+Cr nanoparticles doped with different concentrations of Cr

图3 不同掺Cr浓度的ZnS:Co+Cr纳米晶在紫外光区(a)及可见光区(b)的吸收图谱

Fig. 3 Absorption spectra of ZnS:Co+Cr nanoparticles doped with different concentrations of Cr in UV-Vis region (a) and visible light region (b)

图4 ZnS:Co+Cr(0.75at%) 纳米晶的光学禁带计算

Fig. 4 Plots of (αhν) vs (hν) of ZnS:Co+Cr (0.75at%) nanoc-rystals

图5 不同掺Cr浓度的ZnS:Co+Cr 纳米晶的PL光谱

Fig. 5 PL spectra of ZnS:Co+Cr nanocrystals doped with different concentrations of Cr

图6 不同反应温度的ZnS:Co+Cr (0.75%)纳米晶的PL光谱

Fig. 6 PL spectra of ZnS:Co+Cr (0.75%) nanocrystals synthesized at different temperatures

图7 ZnS:Co+Cr(1at%)纳米晶的XPS能谱

Fig. 7 X-ray photoelectron spectra of ZnS:Co+Cr (1at%) nanocrystals

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