水热法合成AgInS2/ZnS核/壳结构量子点及其荧光性能

Hydrothermal Synthesis and Fluorescence Properties of AgInS2/ZnS Core/Shell Quantum Dots

以硫脲为硫源,采用谷胱甘肽(GSH)和柠檬酸钠(SC)为配体,通过水热法制备了水溶性AgInS2/ZnS(AIS/ZnS)核/壳结构量子点。系统研究了反应温度和配体用量对量子点的合成及其荧光性能的影响。采用X射线衍射(XRD)、透射电子显微镜(TEM)、紫外可见吸收光谱(UV-Vis)和光致发光光谱(PL)分别对量子点的物相、形貌和光学性能进行了表征,并考察了量子点的稳定性。实验结果表明,随着反应温度从70℃升高至90℃,促进了ZnS壳层的形成,有效地钝化了量子点的表面缺陷,获得的AIS/ZnS核/壳量子点的发光强度显著提高,发光峰位从600 nm蓝移至580 nm。配体的添加可以有效地平衡Zn^2+的化学反应活性,减缓ZnS壳层的生长,抑制核壳界面缺陷的形成,还能消除量子点的表面态,当nGSH/nZn^2+=2.0,nSC/nZn^2+=2.5时,AIS/ZnS量子点的荧光性能最佳。此外,AIS/ZnS核/壳结构量子点还具有优异的光学稳定性。

Water-soluble AgInS2/ZnS(AIS/ZnS)core/shell quantum dots(QDs)were synthesized by hydrothermal method using thiourea(TU)as sulfur source,glutathione(GSH)and sodium citrate(SC)as ligands.The effects of reaction temperature and addition amount of ligands on the synthesis and fluorescence properties of AIS/ZnS QDs were systematically studied by XRD,TEM,UV-Vis absorption spectra and PL spectra,respectively,and their stability was also investigated.The results show that the emissive intensity of AIS/ZnS core/shell QDs is significantly improved by increasing the reaction temperature from 70 to 90℃.The increase of temperature promotes the growth of ZnS shell,on which the surface defects is effectively passivated.Meanwhile,the emissive peak showed a blue-shift from 600 nm to 580 nm.Furthermore,the ligands could balance the chemical reactivity of Zn^2+,slow the growth rate of ZnS shell,inhibit the interface defects formation and eliminate the surface states.The AIS/ZnS core/shell QDs showed the strongest emission with nGSH/nZn^2+of 2.0 and nSC/nZn^2+of 2.5.Importantly,the obtained AIS/ZnS core/shell QDs exhibited excellent optical stability.