A bridge role of Tb3+ in broadband excited Sr3Y(PO4)3:Ce3+, Tb3+, Sm3+ phosphors with superior thermal stability

Publication date: 15 March 2017
Source:Materials & Design, Volume 118
Author(s): Zhihua Leng, Liping Li, Xiangli Che, Guangshe Li
In this work, we report on a comprehensive study about the bridge role of Tb³⁺ in broadband excited Sr3Y(PO4)3:Ce³⁺, Tb³⁺, Sm³⁺ phosphors. With Tb³⁺ acting as an energy transfer bridge, Ce³⁺→(Tb³⁺)n→Sm³⁺ energy transfer process was utilized to circumvent Ce³⁺-Sm³⁺ metal-metal charge transfer (MMCT) quenching in Sr3Y(PO4)3 host. Sm³⁺ was efficiently sensitized by the broad absorption band (4f¹→5d¹ transition) of Ce³⁺ in near-ultraviolet spectral region. The color tones of Sr3Y(PO4)3:Ce³⁺, yTb³⁺, zSm³⁺ phosphors were tuned from blue through green and finally to orange with increasing Tb³⁺/Sm³⁺ doping concentration. Furthermore, energy transfer mechanisms from Ce³⁺ to Tb³⁺ (dipole-dipole mechanism) and Tb³⁺ to Sm³⁺ (exchange interaction) as well as the corresponding energy transfer efficiencies (higher than 90%) are systematically investigated. Sr3Y(PO4)3:0.02Ce³⁺, 0.90Tb³⁺, 0.02Sm³⁺ phosphor shows a thermal stability up to 493K, superior to that in analogous reports. The quantum efficiency of Sr3Y(PO4)3:0.02Ce³⁺, 0.90Tb³⁺, 0.02Sm³⁺ phosphor with 315nm excitation was calculated to be 60%.

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