Luminescence enhancement and tunable color emission in Eu/Dy/Sm codoped CaW1- xMoxO4 phosphor

Abstract

• A series of Eu 3+ activated CaMoxW1-xO4 phosphors were prepared. • The influence of [MoO 4 ] addition on the vibrational pattern, band gap and luminescence emission was studied. • The energy transfer from [WO 4 ] to Eu 3+ through the [MoO4] as sensitizer was discussed. • The enhancement of color tunability was reported in this paper. A series of Eu 3+ - activated CaW 1-x Mo x O 4 phosphors possessing schellite type crystalline structure were synthesized by using hydrothermal method to study the influence of molybdate doping on the luminescent performances of CaWO 4 :Eu 3+ phosphors. The phase composition, vibrational spectra and luminescent properties were characterized by X-ray diffraction, fourier transform infrared, and photoluminescence spectroscopy. The addition of [MoO 4 ] does not affect the crystalline phases of the synthesized materials. The effect of addition of [MoO 4 ] into the (Ca,Eu)WO 4 on the band gap of the phosphor and Eu 3+ emission has been studied. The strongest emission at 618 nm is corresponding to 5 D 0 → 7 F 2 transition of Eu 3+ under 273 nm excitation indicating that the site symmetry of the Eu 3+ ions was not affected. A red shift in the excitation spectra of the [WO 4 ] was observed with increasing [MoO 4 ] content. Further, color-tunable emissions were also studied by the co-doping of Dy 3+ and Sm 3+ into the (Ca,Eu)W 0.80 Mo 0.20 O 4 phosphor indicating the potential candidate for light emitting diodes.