Tunable luminescence and energy transfer properties of a novel Na4Ca4Si6O18:Ce3+,Mn2+ phosphor

Abstract

A series of color-tunable Na₄Ca₄Si₆O₁₈:Ce³⁺,Mn²⁺ phosphors were synthesized via a high-temperature solid-state reaction. The effect of Ce³⁺ concentration on the emission intensity of Na₄Ca₄Si₆O₁₈:Ce³⁺ is studied, and the energy transfer from Ce³⁺ to Mn²⁺ is observed. The emission spectra of the Na₄Ca₄Si₆O₁₈:Ce³⁺,Mn²⁺ phosphors show a blue band at 430 nm of Ce³⁺ and a red band at 590 nm of Mn²⁺, originating from the allowed 5d → 4f transition of the Ce³⁺ ion and the ⁴T_1g(4G) → ⁶A_1g(6S) transition of the Mn²⁺ ion, respectively. Non-radiative transitions between the Ce³⁺ and Mn²⁺ ions in the Na₄Ca₄Si₆O₁₈ host are demonstrated to be dipole–quadrupole interactions. Results indicate that the varied emitted color from blue to red can be achieved by tuning the relative ratio of the Ce³⁺ to Mn²⁺ ions based on the principle of energy transfer. We have demonstrated that Na₄Ca₄Si₆O₁₈:Ce³⁺,Mn²⁺ phosphors can be promising candidates for color-tunable phosphors applied in near-UV white LEDs.