Facile synthesis of high-pressure polymorph β-YB3O6 by co-doping Bi3+ and RE3+ (RE = Tb, Eu) with color-tunable emissions via energy transfer

The high-pressure polymorph of beta-YB3O6 was stabilized by doping Bi3+ under ambient pressure, thus solid solutions of beta-Y1-mBimB3O6 (0.10 <= m <= 0.30), beta-Y0.80-xBi0.20TbxB3O6 (0.05 <= x <= 0.80), and beta-Y0.80-yBi0.20EuyB3O6 (0.05 <= y <= 0.80) were prepared simply by high temperature solid state reactions. The phase purity and the successful cationic substitutions were confirmed by powder X-ray diffraction, where the linear expansion of lattice parameters was observed due to the replacement of Y3+ by lager cations. The second function of Bi3+ was to behave as a photoluminescent activator giving the blue emission, as well as a sensitizer to Tb3+ and Eu3+, which emit green and red light, respectively. Bright and color-tunable emissions from blue to green (or blue to red) were achieved by manipulating the relative ratio between Bi3+ and Tb-3+ (or Eu3+). In final, a white emission was observed for the triply-doped phosphor beta-Y0.49Bi0.20Tb0.30Eu0.01B3O6.