Luminescence efficiency enhancement of BaZr(BO3)2:Eu with Si or Al addition

Si4+ and Al3+ doped BaZr(BO3)2:Eu phosphors were prepared by solidstate reaction. BaZr(BO3)2:Eu3+, BaZr(BO3)2:Eu3+, Si4+ and BaZr(BO3)2:Eu3+, Al3+ were characterized by X-ray diffraction spectra (XRD) and photoluminescence spectra. After codoped with Si or Al, the charge-transfer state (CTS) band of Eu3+-O(2-) shows blue shift accompanied by increasing intensity due to shorter ionic radius and stronger electro negativity of Si or Al compared with Zr4+. The high value of asymmetric ratio R(2-1) and omega2 of BaZr(BO3)2:Eu3+ with Si or Al codoping indicates a less symmetrical local structure of Eu3+. This implies that the quantum efficiencies of the 5D0 level of these complexes can be enhanced by doping with Si and Al respectively. Calculation of the Judd-Ofelt parameters of Eu3+ under different crystal fields gives similar results.