A novel self-activated white-light-emitting phosphor of Na2TiSiO5 with two Ti sites of TiO5 and TiO6

Abstract

In this work, a novel self-activated light emitting phosphor of Na₂TiSiO₅ (NTSO) has been successfully synthesized in a high temperature solid-state reaction. The photoluminescence (PL) and cathodoluminescence (CL) properties of NTSO have been measured. Under excitation at 260 nm, NTSO emits a white light with CIE chromaticity coordinates (0.275, 0.355) and cyan light can also be observed at low voltage excitation. The crystal structure of NTSO has been investigated using the Rietveld refinement, which shows that Ti ions not only occupy the octahedron center but also connect with five O ions to form a TiO₅ polyhedron. The special polyhedron of TiO₅ broadens the emission band, and the energy transfer between the two sites has also been proved through the time-resolved photoluminescence (TRPL) spectra. Finally, the CL properties of NTSO with the functions of accelerating voltage, filament current and electron radiation time have been measured and the results show that NTSO emits bright light, and has excellent stability and good CIE chromaticity coordinates, which indicates that NTSO has the potential to be applied in FEDs.