Color tuning and energy transfer investigation in Na2Ca4Mg2Si4O15:Eu2+, Mn2+ phosphor and its potential application for UV-excited UV-WLEDs

Abstract

In this paper, a novel single-phased white light emitting phosphor Na₂Ca₄Mg₂Si₄O₁₅:Eu²⁺, Mn²⁺ was prepared successfully via the high temperature solid state reaction. The obtained Na₂Ca₄Mg₂Si₄O₁₅:Eu²⁺ phosphor exhibits a broad excitation band ranging from 200 to 450 nm and a blue light emission band peaking at 480 nm, originating from 4f⁷ ↔ 4f⁶5 d¹ (f-d) electric dipole allowed transitions of Eu²⁺ ions. Due to the energy transfer from Eu²⁺ to Mn²⁺ ions, the co-doped Eu²⁺ ions in the Na₂Ca₄Mg₂Si₄O₁₅:Eu²⁺, Mn²⁺ phosphors markedly enhances the luminescence intensity of Mn²⁺ ions, providing highly attractive tunable color. The luminescent mechanism invoking the energy transfer between Eu²⁺ ions and Mn²⁺ ions has been certified to be dipole–quadrupole interaction predominantly through the investigations of the luminescence spectra and the fluorescence decay curves. Our results show that the novel Na₂Ca₄Mg₂Si₄O₁₅:Eu²⁺, Mn²⁺ phosphor is a very promising candidate for UV white light emitting diodes.