通过改变基质阳离子半径使O~(2-)→Eu~(3+)电荷迁移带红移

采用高温固相法在1 300℃合成了A_(0.98)Nb_2O_6∶Eu_(0.02)(A=Ca,Sr,Ba)荧光粉。X射线衍射(XRD)的结果表明烧结后得到的产物为纯相。利用稳态荧光光谱(PL)和漫反射光谱(DRS)对A_(0.98)Nb_2O_6∶Eu_(0.02)(A=Ca,Sr,Ba)的发光性质进行了研究。结果表明A_(0.98)Nb_2O_6∶Eu_(0.02)(A=Ca,Sr,Ba)荧光粉可以发射Eu~(3+)的特征红光,光强度按Ca Nb_2O_6Sr Nb_2O_6Ba Nb_2O_6从大到小排列。激发光谱中可以观察到Eu~(3+)离子的电荷转移跃迁(CT)和f-f跃迁吸收。其中CT吸收峰因基质阳离子半径的增大而发生了较大程度的红移,从270 nm红移到了330 nm。

Red shift of O2-→Eu3+ Charge Transfer Band by Changing The Host Cationic Radiu

The phosphors with general molecular formula A0. 98 Nb2 O6:Eu0. 02 ( A=Ca, Sr, Ba) were prepared by the high-temperature solid state reaction technique. X-ray diffraction ( XRD) results re-veal that the obtained products are pure phase. The luminescence properties of A0. 98 Nb2 O6:Eu0. 02 ( A=Ca, Sr, Ba) were investigated by photoluminescence spectra( PL) and diffuse reflection spec-tra( DRS) . A0. 98 Nb2 O6:Eu0. 02 ( A=Ca, Sr, Ba) phosphors can exhibit the characteristic red emis-sion of Eu3+, and PL intensities of A0. 98 Nb2 O6: Eu0. 02 are in the order of CaNb2 O6 >SrNb2 O6 >BaNb2 O6 . The charge transfer transition( CT) and f-f transition absorption of Eu3 + can be observed in the excitation spectra. With the increase of the host cationic radius, the CT band shows large red shift from 270 to 330 nm.