Luminescence properties and high thermal stability of tunable blue–green-emitting phosphor Gd4.67Si3O13:Ce3+, Tb3+

Abstract

A novel phosphor Gd4.67Si3O13:Tb3+, Ce3+ has been prepared by a high temperature solid-state method at 1350°C for 6h. X-ray diffraction (XRD), and Rietveld refinement is used to characterize crystal structure of as-synthesized phosphor. Upon 312nm excitation, emission spectrum of Gd4.67Si3O13:0.02Tb3+ shows a series of sharp peaks, corresponding to the 4f–4f transition of Tb3+. Monitoring 544-nm emission, photoluminescence excitation (PLE) spectrum of Gd4.67Si3O13:0.02Tb3+ is composed of a 226-nm broad band and two sharp peaks (272nm and 312nm). Its critical doping content of Tb3+ is 5%. The absorption spectrum and emission spectrum of Gd4.67Si3O13:Ce3+ has broad bands due to the transition between the 4f1 ground state and the 5d excited state. Ce3+ and Tb3+ co-doped phosphor samples have broad excitation range from 200nm to 380nm indicating it can be effectively excited by ultraviolet light, matching with the near-UV LED chips. By adjusting the ratio of Tb and Ce ions, color tunable phosphors from blue to green can be obtained. Chromaticity coordinates and thermal quenching properties are investigated in details. Its intensities decreased to 80% of the initial intensity (50°C) at 150°C and it does not decrease to half at 300°C, indicating high thermal stability. All the results indicate that Gd4.67Si3O13:Ce3+, Tb3+ phosphor have a potential application for near-UV LEDs.