Ge4+, Eu3+-codoped Y2SiO5 as a novel red phosphor for white LED applications

The phosphors Y2SiO5: Ge4+, Eu3+ were synthesized by solid state reaction method assisted by flux, and have been characterized by X-ray powder diffraction and fluorescence spectrometer. The results showed that the phosphors can be effectively excited by near-UV (394 nm), and the major peak is located at 611nm ascribed to the electric-dipole D-5(0) -> F-7(2) transition of Eu3+, the critical quenching concentration of Eu3+ in the phosphor is determined to be 15mol% and the critical transfer distance is calculated as 8.90 angstrom. Co-doping Y2SiO5: Eu3+ with Ge4+ helps to improve the luminescence intensity and color purity. The red emission of the phosphor under 394 nm excitation shows a good chromaticity index (0.652, 0.347) compared to commercial red phosphors Y2O2S: Eu3+ (0.631, 0.350). The quantum efficiency of the Y2Si0.97O5: 0.03Ge(4+), 0.15Eu(3+)phosphor under 394nm excitation is estimated to be 45.24%. It can be concluded that efficient red light emitting diodes were fabricated using Ge4+, Eu3+ co-doped phosphor based on near ultraviolet(NUV) excited LED lights. (C) 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim