Eu^(3+)掺杂的α-Gd_2(MoO_4)_3荧光粉合成与表征

Synthesis and Characterization of Eu^(3+)Doped α-Gd_2(MoO_4)_3 Phosphor

采用固相反应法合成了Eu3+掺杂的α-Gd2(MoO4)3荧光粉。通过XRD、SEM以及激发和发射光谱对样品进行了研究,结果发现助熔剂为3%时样品的结晶较好,样品的发光强度最强,并且样品粉末不团聚。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,其f-f跃迁的465,395nm吸收更强,这就意味着该类荧光粉可作为目前已商品化的白光LED的红色补偿荧光粉,也可作为近紫外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 α-Gd2 （MoO4 ）3： Eu^3＋ was prepared by solid-state reaction, using the NH4F as the flux. The effects of flux content and concentration of activator on the crystal structure, morphology and luminescent properties were investigated by using XRD, SEM, and fluorescent spectra. The XRD patterns showed that the resultants have the monoclinic phase, and with the increase of the flux amount the crystallization could be improved greatly. The SEM images indicate that the morphology of the phosphor particle is close to ball-like, and thier mean size is around 2 μm. It is also observed that higher flux amount could result in agglomeration of phosphor particles. These results suggest that proper amount of flux should be around 3%. The excitation spectra show effective absorption wavelengths at ultraviolet （UV） （395 nm） and blue （465 nm） corresponding to the f-f transition of Eu^3＋ These wavelengths coincide with the wavelengths of commercial GdN based LED, so that the phosphor may be a better candidate for red component for white LED. The emission spectra exhibit most intense emission at 613 nm, which is assigned to the ^5D0→^7F2 transition. The intense electric dipole transition implies that the Eu^3＋ occupies non-centrosymmetric sites in the matrix. The dependence of emission intensity on the flux was investigated. The better choice for introducing flux was confirmed to be at 3% ,which is in a good agreement with the result derived from the XRD and SEM. Higher quenching concentration was showed to be 40% by studying the dependence of luminescent intensity on the Eu^3 ＋ concentration.