Tunable luminescence and energy transfer properties of Ca5(PO4)2SiO4:Ce3+/Tb3+/Mn2+ phosphors

Abstract

A series of single-composition phosphors Ca₅(PO₄)₂SiO₄:Ce³⁺, Tb³⁺, Mn²⁺ have been prepared via a high-temperature solid-state reaction process. The Ce³⁺ emission at different lattice sites has been identified and discussed. The energy transfer from Ce³⁺ to Tb³⁺ and Mn²⁺ ions has been validated. The emissive colors of Ca₅(PO₄)₂SiO₄:Ce³⁺, Tb³⁺/Mn²⁺ samples can be adjusted from blue to green and from blue to red-orange by the energy transfer of Ce³⁺ → Tb³⁺ and Ce³⁺ → Mn²⁺, respectively. More importantly, white emission has been obtained through adjusting the relative concentrations of Ce³⁺, Tb³⁺ and Mn²⁺ ions in the Ca₅(PO₄)₂SiO₄ host under UV and low-voltage electron beam excitation, respectively. Additionally, the temperature-dependent photoluminescence and the degradation behaviors of cathodoluminescence under continuous electron bombardment for as-prepared phosphors have been investigated in detail. The results reveal that the Ca₅(PO₄)₂SiO₄ host is stable enough to protect the photoluminescence and cathodoluminescence properties of Ce³⁺, Tb³⁺ and Mn²⁺ ions from being affected. Tunable luminescence and the stable structure suggest that Ca₅(PO₄)₂SiO₄:Ce³⁺/Tb³⁺/Mn²⁺ phosphors have great potential in the application in WLEDs and FEDs.