碳热还原法合成LaSi_3N_5∶Ce~(3+)蓝色荧光粉及其发光性能研究

利用碳热还原法制备了LaSi_3N_5∶Ce~(3+)蓝色荧光粉,重点研究了原料中掺C量和退火对样品纯度及发光性能的影响。通过X射线衍射仪和荧光光谱仪分别表征样品的晶体结构和发光性能。研究结果表明:1 600℃时能够合成主相为LaSi_3N_5∶Ce~(3+)的荧光粉。在360nm紫外光激发下样品可获得波段范围在380~600nm的单峰宽带发射谱,归结于Ce~(3+)的5d-4f的能级跃迁。当n_C/n_(La)=4/1时样品发光强度达到最大,并且光谱出现先红移后蓝移的现象。经过退火的样品的发光强度与退火前相比提高了60%~345%。将热处理后的n_C/n_(La)=4/1的样品与商用YAG混合涂覆在UV芯片上(λ_(em)=365nm)封装成WLED,证实了LaSi_3N_5∶Ce~(3+)在白光LED领域潜在的应用价值。

Syntheses and Photoluminescence Properities of LaSi3 N5 : Ce3+ Blue Phosphors by Carbothermal Reduction Method

LaSi3 N5 :Ce3 + blue phosphors were prepared by carbothermal reduction method.The influence of C content and heat-dealing on purity and luminescence of samples were investigated.The phosphors were characterized by X-ray diffraction (XRD) and fluorescence spectrophotometer (PL).XRD patterns revealed that LaSi3 N5 :Ce3 + could be combusted at 1600 ℃.There was a single-peak broadwide emission spectrum between 380~600 nm due to the electron transfer of Ce3 + from 5d-4f excited by 360 nm.The luminescence intensity reached the maximum value atn C/n La =4/1 followed by a continuous decline with a red shift and then a blue shift appeared in the spectrum.The luminescence intensity of samples improved 60%~345% after heat-dealing. WLED were fabricated by applying a blend mixture of the sample and commercial YAG on a UV chip (λblend m),which indica-ted that LaSi3 N5 :Ce3 + blue phosphor had a potential application value in WLED.