Enhanced red emission of Yb, Ho: NaYGd(WO4)2 phosphors by codoping Ce3+

In this work, Yb, Ho, Gd3+/Gd3+, Ce3+: NaY(WO4)2 phosphors doped with various concentrations of Gd3+ and Ce3+ ions were prepared via high-temperature solid-state method. Under the excitation of 980 nm near-infrared light, the doping of Gd3+ ions enhances the red and green emission of Yb, Ho: NaY(WO4)2, and on this basis, the Y3+ ion is replaced by Ce3+ ion doping, the red upconversion emission intensity was enhanced with Ce3+ concentration increasing. It was found that two efficient cross-relaxation processes between Ho3+ and Ce3+ ions had been employed to enhance red emission and suppress green emission. The possible upconversion mechanisms between Ho3+ and Ce3+ ions were investigated in detail. Yb3+, Ho3+, Gd3+, Ce3+ co-doped NaY(WO4)2 phosphors have broad application prospects in the fields of anti-counterfeiting and display, magnetic resonance imaging and optical temperature sensors.