Highly efficient green-emitting phosphors with high color rendering for WLEDs

Abstract

Despite significant progress has been made in the luminescent materials for white light emitting diodes (WLEDs), it is still desirable to develop novel highly efficient phosphors with appropriate excitation and high visible emission for high color rendering WLEDs. In this study, we report a novel phosphor BaGa2Si2O7:Ce3+,Tb3+ (BGSO:Ce3+,Tb3+) with highly effective green luminescence. BGSO:Ce3+,Tb3+ phosphor represents a broad excitation band in the range of 300–400 nm and intense emission at approximately 542 nm with a high photoluminescence quantum efficiency of 76.4%. The structure, luminescence, and energy transfer from the Ce3+ and Tb3+ ions were investigated in detail. Moreover, the incorporation of Na+ or K+ ions into BGSO:Ce3+,Tb3+ for charge compensation can improve the emission intensity and thermal stability. Moreover, a near ultraviolet (n-UV) pumped prototype WLED device was fabricated and it exhibited bright warm-white light with CIE chromaticity coordinates of (0.3561, 0.3344), high color-rendering index (Ra=90.4), and low CCT (3330 K) upon 20 mA driving current. This work provides a new strategy to develop high-quality solid-state LED phosphors.