白光LED用红色发射荧光粉Gd2(MoO4)3：Eu^3＋制备与表征

Synthesis and Characterization of Eu^(3+) Doped Gd_2(MoO_4)_3 Phosphor for White LED Applications

以NH4F为助熔剂采用固相反应法合成了Eu3+掺杂的-αGd2(MoO4)3荧光粉。研究了引入不同含量助熔剂时对材料的结晶、荧光粉颗粒粒径、表面形貌及光谱性质的影响。实验结果表明,引入重量比为3%时样品具有好的结晶和优良的光谱性质;同时,随着助熔剂量的增加Eu3+离子在晶体中所处的格位对称性发生了变化;另外,通过Eu3+掺杂浓度变化的结果讨论了Eu3+的浓度猝灭行为。光谱测量的结果表明,该荧光粉与其他商品荧光粉不同,其最有效的激发波长不在电荷迁移带范围,而是465和395 nm跃迁,该荧光粉可作为近紫外LED和三基色荧光粉组合型白光器件的红色荧光粉的候选材料。

A novel red emitting phosphor Gd2（MoO4）3 ： Eu^3＋ was prepared by a solid reaction, using NH4F as flux. The effects of flux content and concentration of activator on the crystal structure, morphology and luminescent properties were investigated by XRD, SEM, and fluorescent spectra. The XRD patterns showed that the resultants had the monoclinic phase structure, and with increasing the flux amount the crystallization could be improved greatly. The SEM images indicated that the morphology of the phosphor particle was quasispherical, and their mean size was around 2 μm. It was also observed that higher flux amount could result in agglomeration of phosphor particles. These resultssuggested that proper amount of flux should be around 3 %. The excitation spectra showed effective excitation wavelengths at UV （395 nm） and blue （465 nm） corresponding to the f-f transition of Euμ . These wavelengths coincided with the wavelengths of commercial GaN based LED, so that the phosphor might be a better candidate for red component for white LED. The emission spectra exhibited most intense emission at 613 nm, which was assigned to the ^5D0→^7TF2 transition. The intense electric dipole transition implied that the Eu^3＋ occupied non-centrosymmetric sites in the matrix.