The electronic structure and tunable emission of self-activated white-light-emitting Na2TiSiO5 phosphor

The exploration of rare-earth-free phosphors is desirable for white LEDs applications. In this work, Cr³⁺ doped Na₂TiSiO₅ self-activated phosphors were synthesized by conventional solid-state reaction. The electronic structure of Na₂TiSiO₅ was calculated using density functional theory (DFT) methods. The variations in crystal structure, luminescence properties and thermal stability of Na₂Ti_1-xSiO₅: xCr³⁺ were exhaustively investigated by the analysis of XRD patterns, photoluminescence (PL) spectra, diffuse reflection spectra, PL decay curves and temperature-dependent PL spectra. Owing to the red shift of absorption edge and energy transfer between Cr³⁺ ions and Ti⁴⁺ ions, the emission intensity and thermal stability of Na₂TiSiO₅ were improved by the introduction of Cr³⁺ ions, and the peak position was red-shifted. The results indicate that the introduction of Cr³⁺ ions could be an effective method to regulate the luminescence of Ti⁴⁺-activated oxide phosphors.