Eu3+/Eu2+/Tb3+ co-activated single-phase Gd2O2S: A high-performance white light emitting phosphor for light emitting diode

In this work, we report Eu3+/Tb3+/Eu2+ co-activated Gd2O2 S as novel phosphor materials that can be effectively applied in the white-light emitting diode based on a near-UV chip with sensational performances. The luminescent properties and energy transfer mechanism have been thoroughly investigated. The as-prepared europium/terbium co-doped Gd2O2 S phosphors exhibit strong fluorescence with tunable color output under UV-vis light excitation. Furthermore, a high response to ultraviolet illumination of 398 nm wavelength was observed in the excitation spectra, indicating an excellent match with a light-emitting-diode chip in the dominant emissions. It is found that a tricolor (blue, green and red) emission band which results in a white light emission can be acquired when Eu3+, Eu2+ and Tb3+ ions are all co-doped into the single phase Gd2O2S, and an optimum ion doping level (10 at.% Eu and 0.7 at.% Tb) can effectively emit nearly pure white color photoluminescence with lifetime effectively tuned from 0.55 ms to 1.10 ms. The CIE (Commission International de I'Eclairage 1931 chromaticity) is X = 0.3507, Y = 0.3029. It is therefore expected that the newly found phosphor material with high-performance properties possess great potentials for the future advanced white LED applications.