Bi³⁺浓度对Y₂O₃基荧光粉发光性能的影响

Y₂O₃:xBi³⁺ (x=0.05-1.0% (mole fraction)) phosphors were synthesized by a solid-phase reaction route. Effect of Bi³⁺ concentration on the phase composition, microstructure and photoluminescence (PL) performance was investigated. The results show that the lattice parameter and cell volume of Y₂O₃ host increase with the increase of Bi³⁺ concentration. In addition, the phosphors are equiaxed grains, and the grain size increases gradually from 250 to 600 nm with the Bi³⁺ concentration increasing. The emission spectra of Y₂O₃:Bi³⁺ phosphors excited by ultraviolet light (λ_EX=335 nm) are composed of three broadband emission spectra centered at 370 nm, 410 nm and 483 nm. The ultraviolet-emission at 370 nm and blue-light emission at 410 nm appear due to ³A_u→¹A_g and ³E_u→¹A_g electron transitions of S₆ sites of Bi³⁺, respectively. The blue-green emission at 483 nm occurs due to ³B→¹A electron transition of C₂ sites of Bi³⁺. The Y₂O₃:0.25%Bi³⁺ phosphor shows the optimal PL performance. The concentration quenching occurs when Bi³⁺ concentration is higher than 0.25% due to the dipole-dipole interaction between Bi³⁺ ions. The color coordinate of Y₂O₃:0.25%Bi³⁺ is (0.159 2, 0.218 1), and the color rendering index Ra is 69.27, indicating that the as-synthesized blue-green phosphors have a broad application prospect in the field of white light-emitting diode.