SiO_2干凝胶中CdS量子点的光致发光性质

Photoluminescent Properties of CdS Quantum Dots Doped in Silica Xerogel

以正硅酸乙酯(TEOS)为SiO2的前驱物,硝酸镉为镉源,硫脲为硫源,用溶胶-凝胶法制备了CdS量子点掺杂的SiO2干凝胶,利用XRD、紫外-可见吸收光谱、光致发光谱对其性质进行研究。样品的测试结果表明在SiO2干凝胶的网状结构中形成了CdS量子点,平均粒径为5.1 nm。SiO2凝胶中CdS吸收峰位置明显蓝移。在一定浓度范围内,SiO2干凝胶中CdS量子点的光致发光强度随着掺杂量的增大而增强,当掺杂摩尔分数达到0.5%时,其荧光增强效应达到最大;随后,其发光强度开始减弱。

The CdS nanocryticles doped silica xerogels were prepared by using the sol-gel method,where tetraethoxysilane（TEOS） was employed as the main precursor and cadmium nitrate,thiourea as start materials.The X-ray diffraction pattern indicated that silica xerogels are noncrystalline structure and the mean diameter of the CdS particles is 5.1 nm.The PL emission spectrum of the undoped silica xerogels showed weak emission peaked at 460 nm that could be attributed to the intrinsic defect states of silica xerogel.For 0.5% CdS-doped samples,the photoluminescence intensity reached maximum.The PL excitation spectra of undoped silica xerogel show that only one peak at 350 nm is observed.For CdS-doped samples,a new peak at 380 nm is observed,which could be attribute to the doping CdS quantum dots.