采用工业频率为2.45 GHz的高温微波法制备了纯基质相的CaS∶Eu2+红色发光材料, 激发波段为410～580 nm, 发射峰值波长为654 nm。在微波输入功率为1.0～1.1 kW的条件下, 可以获得纯基质相CaS∶Eu2+发光材料; 在1.2～1.3 kW功率范围, 获得的样品中含有CaO杂质相, 且颗粒团聚严重。其中, 1.1 kW制备的CaS∶Eu2+样品相纯度最高, 发光性能最优。微波功率的变化本质上揭示了固体颗粒的介电损耗因子及其加热特性的变化, 体系涉及的非平衡反应机制促使了纯基质相的形成, 并影响材料晶相结构、粒径、形貌和发光性能。结果显示, 高温微波制备技术通过控制输入功率及其物料的介电损耗性质, 能够获得纯基质相并且颗粒小、团聚少的荧光粉。

Classical blue-green excitable CaS∶Eu2+ phosphor with desired red emission was synthesized by microwave (MW) field with a high frequency of 2.45 GHz. The phosphors can be excited in a wavelength range from 410 nm to 580 nm. In particular, the phosphors exhibit a 476 nm excitable 654 nm peaked red emission. The effect of MW power on material crystal structure, particle size, morphology and luminescent properties was researched by varying the firing power of MW. It has been established that the dielectric property of materials affects MW heating process. MW power supply acts as an effective indicator to predict the viability of dielectric property of materials due to the MW energy. The results show that the variation of MW power can not affect the crystal field of Eu2+ in lattice matrix. It is obvious that the phase purity, particle size, and morphology are different with the variation of applied MW power. The phase purity CaS∶Eu2+ phosphor with smaller particle size can be obtained in the MW power range of 1.0 kW to 1.1 kW. However, the samples contain CaO impurity phase and the particles are severely agglomerated in the MW power range of 1.2 kW to 1.3 kW. In conclusion, a maximum PL intensity at 1.1 kW of MW power is acquired for the obtained purer host phase.