Exporing upconversion luminescence properties of Yb³⁺/Er³⁺ Co-doped SrWO₄ phosphors: microstructural, morphological and mechanisms

Abstract

SrWO₄:Yb³⁺/Er³⁺ upconversion luminescent materials with different Yb³⁺/Er³⁺ 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% Yb³⁺ and 2.5% Er³⁺ shows the best luminescence performance. Under 980 nm excitation light environment, the emission peak of the SrWO₄:(0.07)Yb³⁺/(0.025)Er³⁺ sample locates at the orange-red area (650–700 nm), and the color coordinate is (0.5846, 0.4053). In the Yb³⁺/Er³⁺ co-doped SrWO₄ phosphor, the 980 nm laser photons are strongly absorbed by the Yb³⁺ ions and transferred to the ground state Er³⁺ ions via energy transfer process. The present results demonstrate that the SrWO₄:Yb³⁺/Er³⁺ phosphors may be a promising candidate for upconversion white light-emitting diodes (WLEDs).