微波合成的纳米球形CaS∶Ag+荧光体的荧光光谱

在微波场作用下 ,快速合成了CaS∶Ag+荧光体 ,用X射线粉末衍射 (XRD)分析证实了它们是立方晶相。测定了它们的激发光谱和发射光谱 ,发现其发射峰位于 372nm、45 0nm和 5 77nm ,分别是由A′gCa V2 +S 中心的Ag+离子、间隙Ag+离子、A′gCa的Ag+离子和CaS基质自激活产生的 ,随着Ag+的掺杂浓度和助熔剂的改变 ,Ag+离子的几个发光中心互相转化 ,荧光体发出不同颜色的荧光。用扫描电镜 (SEM)观察了它们的晶体形貌和尺寸大小 ,结果表明CaS∶Ag+荧光体的晶体形貌都是球形的 ,但其粒径和晶体的分散性受Ag+的掺杂浓度和助熔剂的影响 ,出现了纳米晶 ( 7～ 10 0nm)和亚微米晶 ( 12 5～ 30 0nm)。

The Fluorescent Spectra of the Spherical CaS∶Ag+ Phosphor with Nano-Scale Synthesized Microwave Radiation Method

The fluorescent spectra of the phosphors CaS∶Ag prepared rapidly by microwave radiation method are studied. The XRD analysis shows that the structure of the phosphors belongs to cubic system. The SEM photographs show that all the CaS∶Ag phosphors possess spherical shapes, but the effect of different fluxes and silver concentrations on crystal size and distribution is different, they are nano-scale (7～100 nm) and submicron-scale (125～300 nm) crystallines. The excitation and emission spectra of the phosphors CaS∶Ag are measured and explained. In emission spectra, three peaks located at 372 nm, 450 nm and 577 nm have been observed, respectively. With different fluxes and with different silver concentrations, the emission spectra of CaS∶Ag phosphors change complicatedly. The peak of 372 nm is produced by AYg′ Ca-V 2 S centers. The peak of 450 nm migrates to shorter wavelength with the increase of silver concentrations. It is caused by interstitial Ag ions. The peak of 577 nm is quenched by increase of silvr concentrations. It is caused by interstitial Ag+ ions. The peak 577 nm is quenched by increase of silver concentrations. It is produced by substitutive Ag+ ions and fundamental emission of CaS. In addition, the good distribution of crystal attributes to the increase of Iblue/Iyellow. During the preparation of CaS:Ag+ in microwave field, three colors powders have been obtained. They are white powder, light gray and brown. The quantitative analysis based on their XRD experimental data shows that the microwave reaction mechanism is that the diffusions of ions in the microwave field are enhanced.