近紫外宽带激发LED用红色荧光粉(Gd_(1-x)Eu_x)6(Te_(1-y)Mo_y)O_(12)的制备与性能  

Preparation and photoluminescent properties of near-UV broadband-excited red phosphor(Gd_(1-x)Eu_x)_6(Te_(1-y)Mo_y)O_(12) for white-LEDs

作　　者：吕兆承[1] 李营[1] 全桂英[1] 郑庆华[1] 周薇薇[1] 赵旺[1] 

机构地区：[1]淮南师范学院电子工程学院,淮南232038

出　　处：《物理学报》2017年第11期305-311,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61205213;21201071);安徽省自然科学基金(批准号:1708085QE91);安徽省高等学校自然科学研究重点项目(批准号:KJ2016A673);安徽省高校优秀青年人才支持计划重点项目(批准号:gxyq ZD2016259;gxyq ZD2016260);淮南市创新团队建设计划(批准号:2016A24);校级科学研究项目(批准号:2014xj57;2014xj09zd;2015xj11zd)资助的课题~~

摘　　要：利用高温固相法制备了一种新型红色荧光粉(Gd_(1-x)Eu_x)_6(Te_(1-y)Mo_y)O_(12),研究了Eu^(3+)单掺和Eu^(3+),Mo^(6+)共掺Gd_6TeO_(12)荧光粉的结构、形貌和荧光性能.实验结果表明,所合成的粉体为纯相.在393 nm近紫外光激发下,(Gd_(1-x)Eu_x)_6(Te_(1-y)Mo_y)O_(12)荧光粉发出特征红光,位于632 nm处的发射主峰属于Eu^(3+)的~5D_0→~7F_2跃迁.当Eu^(3+)掺杂浓度超过20%(物质的量分数)时发光出现浓度淬灭,经证实这是由电偶极-电偶极相互作用造成的.随着工作温度升高,荧光粉发光强度减小,计算得到Eu^(3+)热淬灭过程中的激活能为0.1796 eV.当(Gd_(0.8)Eu_(0.2))_6TeO_(12)中共掺Mo~(6+_(取代Te^(6+)),该荧光粉发射光谱的峰位、强度变化不大,但是Mo^(6+)-O^(2-)电荷迁移态显著增大了近紫外波段的激发带宽度,可以有效提高激发效率.具有近紫外宽带激发特征的(Gd_(0.8)Eu_(0.2))_6(Te_(0.6)Mo_(0.4))O_(12)是一种潜在的白光LED用荧光粉材料.Generally, the Eu3＋-activated red phosphors suffer narrow of the spectrum, resulting in poor spectral overlapping with the 4f-4f excitation lines ranging from near-UV to blue part emission spectrum of the pumping LED and low energy conversion efficiency. In this paper, the strategy of Te6＋/Mo6＋ mixing is adopted to enhance the excitation bandwidth of Eu3＋ via the energy transfer from Mo6＋-O2- charge transfer state to Eu3＋, which is crucial for LED applications. A series of （Gd1-xEux）6（We1-yMoy）O12 red phosphors are synthesized by the solid state method at 1200 ℃. The crystal structure, morphology and luminescent properties are investigated by means of X-ray diffraction （XRD）, scanning electron microscopy （SEM） and photoluminescent spectrum. The XRD patterns of （Gd1-xEux）6（We1-yMoy）O12（x = 0.2, y = 0, 0.4） match well with that of Gd6TeO12 （JCPDS No. 50-0269）, but differ from that of Gd6MoO12 （JCPDS No. 24- 1085）. The phosphor consists of irregular particles with an average size of 10 μm. Upon excitation at 393 nm, the （Gd1-Eu）6TeO12 phosphors emit red light corresponding to the intraconfigurational 4f-4f transitions of Eu3＋, and the color coordinates are calculated to be （0.647, 0.353）. The 5D0 → 7F2 electron-dipole transition dominates the emission spectrum, which reveals that Eu3＋ occupies a crystallographic site without an inversion center. Moreover, this transition gives rise to three distinguishable emission lines situated at 605, 618, and 632 nm, respectively. This unusual spectral splitting is supposed to originate from the strong interaction exerted by the crystal field of host on the 4f electrons. The optimum doping content of Eu3＋ in （Gdl-xEux）6TeO12 phosphor is 20% （mole fraction）, the critical distance for energy transfer is 0.75 nm, and the concentration quenching is confirmed to be induced by the dipole-dipole interaction from the linear relationship between lg（I/x） and lgx （I represents the luminescence intensity, and x

关 键 词：LED 碲酸盐 高温固相法 红色荧光粉 

分 类 号：O482.31[理学—固体物理] TN104.3[理学—物理]