原材料Y_2O_3的结晶性对Y_2O_2S∶Eu~(3+)发光特性的影响

为进一步提高Y2O2S∶Eu3+的发光性能,采用改善主要原材料Y2O3结晶性的方法,使Y2O2S∶Eu3+红色荧光粉在20 kV和25 kV下发光强度分别增强5%和10%,且不影响色度、粒度、粉体分散性等主要考核指标。提高了粉体的耐电压特性(发射强度与激发电压间的关系特性)。讨论和分析了发射强度增强、电压特性改善的原因:主要原材料Y2O3的结晶性的改善,使得合成的Y2O2S∶Eu3+具有更好的晶体质量,Eu3+离子晶场环境得到进一步改善,从而减弱了无辐射过程及因晶格畸变所造成的能量损失,发光效率得到增强,电压特性得到改善。实验表明,获取高质量多晶Y2O3的最佳分解温度为1400℃左右。

Effects of Crystallinity of Raw Material Y2O3 on Luminescent Character of Y2O2S∶Eu3+

In order to improve the luminescent character of Y2O2S∶Eu3+, the method of improving crystallinity of primary raw material Y2O3 is used. The emission intensity of red phosphors Y2O2S∶Eu3+ is effectively enhanced 5％ and 10％ respectively at the voltages of 20 kV and 25 kV while the other primary properties of application in chromaticity, granularity and decentralization are not changed. The voltage resistance character (relation between emission intensity and excitation voltage) is elevated. The origins of the emission intensity enhancement and excitation voltage elevation are discussed and analyzed preliminarily. It is likely that the abnormal change and defect of crystal lattice led by the substitution of larger radius Eu3+ ion for smaller radius Y3+ ion are reduced by the better crystal quality of Y2O2S∶Eu3+ from the better crystallinity of raw material Y2O3. Because the crystal field condition of Eu3+ ion is improved, radiationless process and energy loss led by crystal defect are cut down, the emission efficiency of Y2O2S∶Eu3+ phosphors is enhanced and its voltage character is improved. The experiment shows that the decomposing temperature to get the high crystallinity Y2O3 is about 1400 ℃.