Exporing upconversion luminescence properties of Yb 3+ /Er 3+ Co-doped SrWO 4 phosphors: microstructural, morphological and mechanisms

SrWO 4 :Yb 3+ /Er 3+ upconversion luminescent materials with different Yb 3+ /Er 3+ doping concentrations were prepared by high temperature solid-sate reaction at 1200 °C for 4 h. X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrometer (PL) were used to characterize the phase structure, surface morphology and luminescent properties of the samples. The sample that contains 7% Yb 3+ and 2.5% Er 3+ shows the best luminescence performance. Under 980 nm excitation light environment, the emission peak of the SrWO 4 :(0.07)Yb 3+ /(0.025)Er 3+ sample locates at the orange-red area (650–700 nm), and the color coordinate is (0.5846, 0.4053). In the Yb 3+ /Er 3+ co-doped SrWO 4 phosphor, the 980 nm laser photons are strongly absorbed by the Yb 3+ ions and transferred to the ground state Er 3+ ions via energy transfer process. The present results demonstrate that the SrWO 4 :Yb 3+ /Er 3+ phosphors may be a promising candidate for upconversion white light-emitting diodes (WLEDs).