ZnS∶Er,Yb量子点的水热法制备及其表面修饰

Study on Hydrothermal Method Preparation and Surface Modification of ZnS∶Er,Yb Quantum Dots

以硫代硫酸钠和亚硫酸钠为反应原料,水热法合成了Er,Yb掺杂的ZnS量子点。利用X线衍射(XRD)、透射电子显微镜(TEM)和荧光分光光度计分别对合成的ZnS量子点的物相、形貌和荧光性能进行分析。研究结果表明,合成的ZnS∶Er和ZnS∶Er,Yb均是ZnS闪锌矿结构,粒径约(5~10)nm,形状近球形。荧光光谱测试结果表明,ZnS∶Er量子点在530nm处获得了Er离子~2 H_(11/2)→~4I_(15/2)能级的发射峰。随着Er的摩尔分数增加,ZnS∶Er量子点的荧光强度先增加后降低,且x(Er)=2%、x(Yb)=1%时荧光效果最好。对掺杂量为x(Er)=2%、x(Yb)=1%的ZnS量子点采用SiO_2进行包覆后,量子点的表面缺陷得到抑制,Er离子的发光峰明显增强,且硅酸乙酯的包覆量为1.5%时发光强度最大。

In this work,using the sodium thiosulfate and sodium sulfite as the reaction raw materials,the Er and Yb doped ZnS quantum dots were prepared by the hydrothermal method.The phase、morphology and fluorescence performance of ZnS quantum dots were analyzed by XRD,TEM and the fluorescence spectrophotometer.The results showed that both the prepared ZnS∶Er and ZnS∶Er,Yb were ZnS blende structure,the grain was near spherical and about（5~10）nm in size.The fluorescence spectral showed the ZnS∶Er quantum dots had a strong emission peak for ~2H_（11/2）→~4I_（15/2） of Er ion energy level at 530 nm.With the increase of Er content,the fluorescence intensity of ZnS∶ Er quantum dots increased firstly and then decreased.The fluorescence effect was optimal with x（Er）=2% and x（Yb）=1%.When the ZnS quantum dots with the doping amount of 2% of Er and 1% of Yb were coated by SiO_2,the surface defects of the quantum dots were suppressed,the luminous peak of Er ion was enhanced obviously,and the luminous intensity was maximum at 1.5% of ethyl silicate coating.