Tunable Luminescence and Ce³⁺ → Tb³⁺ → Eu³⁺ Energy Transfer of Broadband-Excited and Narrow Line Red Emitting Y₂SiO₅:Ce³⁺, Tb³⁺, Eu³⁺ Phosphor

Abstract

The Ce3+ → Tb3+ → Eu3+ energy-transfer process enables Eu3+5D0 → 7FJ line emission to be sensitized by the allowed Ce3+ 4f1 → 5d1 absorption transition in near-ultraviolet (NUV) and violet spectral regions. This energy-transfer strategy is applied in Y2SiO5:Ce3+, Tb3+, Eu3+ powders, leading to line-emitting red phosphors that can be excited by short-wavelength InGaN LEDs. The blue, green, and red colors can be tuned by the ratio of Ce3+/Tb3+/Eu3+. Furthermore, the energy-transfer efficiencies and corresponding mechanisms are discussed in detail, and the thermal stability is evaluated. The results suggest that the optimal composition phosphor Y2SiO5: 0.01Ce3+, 0.50Tb3+, 0.01Eu3+, which exhibits an intense Eu3+ red 4f–4f sharp emission with a strong 4f–5d absorption band of Ce3+ at the NUV region, could serve as a potential broadband-excited and narrow line red phosphor for NUV LEDs.