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

Abstract

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 Na2Ti1-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.