摘要
采用高温固相法合成出系列黄绿色Sr1-yEuySi2O2-zN2+2z/3荧光材料,进行了光学性质表征并探索了其在LED上的应用。在Eu2+掺杂浓度为0～0.200范围内,所合成的化合物为系列色坐标可调的黄绿光-黄光连续固溶体,在250～500nm具有高的激发效率,激发和发射光谱位置及其发射强度随Eu2+浓度改变产生规律性变化;利用光谱理论系统研究了Eu2+的最低5d吸收能级、5d轨道重心移动、晶体场分裂和Stokes位移对激发和发射光谱位置、半峰全宽和荧光寿命的影响及其相互关系。该类荧光材料在77～425K具有良好的温度特性,425K时的发射强度为77K的58%左右。首次将它们和近紫外LED(～400nm)、蓝光LED(～460nm)封装成高亮度黄绿光和黄光LED以及白光LED,发光效率高达19lm/W,这些封装的LED的发光性能也随着Eu2+浓度,以及粉胶比例变化而呈规律性变化。
A series of Sr1-yEuySi2O2-zN2＋2z/3 phosphors were synthesized by the high-temperature solid-state reaction and characterized systematically. The X-ray powder diffraction analysis confirms the formation of a solid solution of Sr1-yEuySi2O2-zN2＋2z/3 phosphor for Eu concentration from 0 to 0.2. The photoluminescence properties show that the phosphors can be efficiently excited by UV-visible light from 250 to 500 nm and exhibit intense tunable yellowish green light due to Eu concentration. The relationship among the lowest 5d absorption bands, Stocks shifts, the centroid shifts and splitting of Eu2＋ levels was studied in details. The temperature dependent emission spectra in the temperature range of 77 - 450 K show that they have a high thermal quenching temperature above 450 K. The LED based on UV/blue chip and Sr1-yEuySi2O2-zN2＋2z/3 phosphors were encapsulated firstly, which show intense green, white and lower UV light emission. Their luminescent properties agree well with these phosphors. The luminous efficiency of the fabricated LED can reach 19 lm/W and the white LED can be obtained from the phosphors fabricated with blue chip based on different gel concentration. These results indicate that Sr1-yEuySi2O2-zN2＋2z/3 phosphors are promising candidates for solid-state lighting LED.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2010年第1期31-38,共8页
Chinese Journal of Luminescence
基金
国家自然科学基金面上(20501023)资助项目
