Blue emission from Sr_0.98Ga₂B₂O₇: 0.01Bi³⁺, 0.01Dy³⁺ phosphor with high quantum yield

Most of the blue phosphors are based on Eu²⁺ or Ce³⁺ doped compounds. The luminescent centers of Eu²⁺ or Ce³⁺ generally require reducing environment during synthesis. Also, Eu²⁺ and Ce³⁺ are prone to oxidation, causing instability of the phosphors for long-term use. Herein, we report Bi³⁺ and Dy³⁺ co-doped SrGa₂B₂O₇ blue phosphors with simpler synthesis conditions and more stable chemical property. In this phosphor, Bi³⁺ ions emit blue light and, while Dy³⁺ as sensitizer has no appreciable luminescence emission but can enhance the emission of Bi³⁺. Co-doping with rare earth ions enhances the emission of Bi³⁺, improving the efficiency and stability of the phosphor. The Sr_0.98Ga₂B₂O₇: 0.01Bi³⁺, 0.01Dy³⁺ phosphor exhibits strong blue light emission with absolute quantum yield of 65.54%. Sr_0.98Ga₂B₂O₇: 0.01Bi³⁺, 0.01Dy³⁺ has a broad excitation band (250–380 nm), emits bright blue light at 430 nm and has a narrow full width at half maxima (FWHM = 64.6 nm) with a color purity of 94.2%. Furthermore, the Sr_0.98Ga₂B₂O₇: 0.01Bi³⁺, 0.01Dy³⁺ phosphor retains strong blue light emission at high temperatures (95% at 100 °C). Overall, Sr_0.98Ga₂B₂O₇: 0.01Bi³⁺, 0.01Dy³⁺ is a promising blue emitting phosphor for n-UV WLED.