摘要
采用高温固相法制备了LiGd(W_yMo_(1-y))_2O_(8-x/2)F_x∶0.4Eu^(3+)(x=0~1,y=0~1)系列白光LED用红色荧光粉。通过扫描电子显微镜、X射线衍射仪、红外光谱仪、荧光光谱仪对荧光粉的形貌、结构、光学性能进行了表征。结果表明,Eu^(3+)、F-和WO_4^(2-)的掺杂没有改变LiGd(MoO_4)_2的四方晶系白钨矿结构;F^-和WO_4^(2-)最佳掺杂量分别为x=0.6,y=0.4。在396 nm激发下,LiGd(W_(0.4)Mo_(0.6))_2O_(7.7)F_(0.6)∶0.4Eu^(3+)的发光强度比未掺杂样品提高了60%,量子效率可达66.23%。当温度升高至100℃时,样品的发射强度降为25℃时的76.6%。在460 nm激发下,样品的最强窄带发射峰位于617 nm处,归属于~5D_0→~7F_2跃迁,色坐标为(0.649 9,0.346 3)。5D0能级的荧光寿命曲线遵循单指数规律衰减,随着F-掺杂浓度的增加,5D0能级的荧光寿命不断增加,归因于低声子能量的F-掺入有效减小了能量的无辐射跃迁概率。所制备的LiGd(W_(0.4)Mo_(0.6))_2O_(7.7)F_(0.6)∶0.4Eu^(3+)荧光粉有望应用于白光LED。
LiGd（ W_yMo_（1- y））_2O_（8-x/2）F_x∶0.4Eu^（3＋）red phosphors with different F-and WO_4^（2-）doping concentrations for white LEDs were synthesized by the solid state reaction method.Morphology,structure,optical properties of Li Gd（ W_yMo_（1-y））_2O_（8-x/2）F_x∶0.4Eu^（3＋）phosphors were studied by scanning electron microscope（ SEM）,X-ray diffraction（ XRD）,Fourier transform infrared spectroscopy（ FT-IR） and fluorescence spectrometer.The results show that the samples doped with Eu^（3＋）,Fand WO_4^（2-）have tetragonal scheelite structure.The optimum doping content of F-and WO_4^（2-）is x =0.6 and y = 0.4,respectively.Under 396 nm excitation,the maximum emission intensity of Li Gd（W_（0.4）Mo_（0.6））_2O_（7.7）F_（0.6）∶0.4Eu^（3＋）in which the quantum efficiency is 66.23% is higher than 60% in comparison with Li Gd（ Mo O4）2∶ 0.4Eu^（3＋）.When the temperature turned up to 100 ℃,the emssion intensity of Li Gd（ W0.4Mo0.6）2O7.7F0.6∶ 0.4Eu^（3＋）is 76.6% of the initial value at 25 ℃.Under 460 nm excitation,intense red emissions corresponding to ~5D_0→~7F_2 transitions of Eu^（3＋）are observed.Thechromaticity coordinates of LiGd（W_（0.4）Mo_（0.6））_2O_（7.7）F_（0.6）∶ 0.4Eu^（3＋）phosphors are（ 0.649 9,0.346 3）.Decay curve of ~5D_0 state for as-prepared samples fits the single order exponential behavior,the lifetime of ~5D_0 increases with the increasing of F-doping concentration,which is due to the reduction of non-radiative transition probability results from the low phonon energy property of F-.LiGd-（W_（0.4）Mo_（0.6））_2O_（7.7）F_（0.6）∶0.4Eu^（3＋）phosphors are suitable for the white LEDs.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2016年第10期1203-1212,共10页
Chinese Journal of Luminescence
基金
江西省高等学校科技落地计划(KJLD14045)
江西省自然科学基金(20132BAB206020)
江西省教育厅科学技术研究项目(GJJ14408)
国家自然科学基金(51304086)
江西理工大学青年英才计划资助项目
