Luminescence properties of Bi3+ doped Lu1-xO3: x%Ho3+ metal ion phosphors

Bi3+ doped Lu1-xO3: x%Ho3+ metal ion phosphors were prepared using the high-temperature solidphase method. The crystal structures of Bi3+ doped Lu1-xO3: x%Ho3+ phosphors, the Bi3+-> Ho3+ energy transfer rule in Lu2O3 matrix and the luminescent properties of synthetic powders with different doping concentrations were investigated. X-ray diffraction results showed that Bi3+ and Ho3+ doping had no effect on the cubic phase structure of Lu2O3. Lu2O3: Ho3+, Bi3+ phosphor emitted S-5(2)-> I-5(8) transition of Ho3+ at 551 nm under an excitation wavelength of 322 nm, and exhibited S-1(0)-> P-3(1) characteristic transition of Bi3+ at 322 nm and I-5(8)-> F-5(1) transition of Ho3+ at 448 nm under an emission wavelength of 551 nm. When the doping concentration of Bi3+ was 1.5%, the effect was most effective for the energy transfer of Ho3+, which increased by a factor of 34.8 compared to that of the single-doped Ho3+ sample. For Lu98.5%-yO3:1.5%Ho3+, y%Bi3+(y=1, 1.5, 2), with the increase of Bi3+ ions concentration, the luminescence intensity at 551 nm under 980-nm excitation increased by a factor of 13.3, 16.8 and 14.2, respectively, compared to that of under 322-nm excitation. The energy transfer critical distance between Bi3+ and Ho3+ was calculated to be 2.979 nm, and the energy transfer between Bi3+ and Ho3+ was achieved by dipole-quadrupole interaction.