CdSe/CdS核壳型量子点的合成及其在白光LED的应用

Synthesis of CdSe/CdS Core/shell Quantum Dots and Their Application for White LEDs

以氯化镉、二氧化硒及硫化钠为原料在水相中直接合成巯基乙酸稳定的CdSe/CdS核壳型量子点,对所合成的核壳量子点的晶体结构、形貌特点及光学特性进行了X线粉末衍射(XRD)、高分辨透射电镜(HRTEM)、紫外可见吸收光谱(UV-vis)和荧光光谱(PL)表征.XRD结果表明合成的CdSe/CdS核壳量子点表现出显著的立方晶系结构CdS的特征峰;TEM结果显示所合成的量子点形貌呈近球状,直径大约6nm.CdSe/CdS量子点发射黄色荧光,其荧光强度是CdSe的10倍左右.将CdSe/CdS量子点与蓝光InGaN芯片组合得到白光发光二极管(LED),所得白光LED的显示指数为77.1,与当前商业用的YAG白光LED相当,说明所合成的CdSe/CdS核壳量子点可作为白光LED备选荧光材料.

The thioglycolic acid-capped CdSe/CdS core/shell quantum dots can be conveniently prepared in aqueous phase using CdCl2.2.5H 2O,SeO 2,Na2S.9H2O as precursor.The size,crystalline structure and optical properties of the as-prepared quantum dots were characterized by high resolution transmission electron microscopy（HRTEM）,X-ray powder diffraction（XRD）,UV-vis absorption（UV-vis）,photoluminescence spectrum（PL）,respectively.The results reveal that,the obtained CdSe/CdS QDs are of cubic crystal structure with a sphere-like shape,and the diameter is about 6nm.The yellow-emitting CdSe/CdS quantum dots with excellent optical property,the intensity of the CdSe/CdS is enhanced about 10 times after capping with CdS shell.White light-emitting diode（WLED） is assembled by blue InGaN chip and QDs,and the color rendering index of the WLED is 77.1.It shows that the as-prepared CdSe / CdS QDs is a good alternative for WLED application.