Influence of Cr3+ on upconversion luminescent and magnetic properties of NaLu0.86-xGd0.12F4:Crx3+/Er0.023+ (0≤x≤0.24) material

Upconversion phosphors can convert near-infrared light into visible emission by sequentially absorbing multiple photons. In most studies, Yb3+/Er3+, Yb3+/Tm3+ ions are used as sensitizer/activator in host materials. In this work, we introduce chromium (Cr3+) ions to NaLu0.86-xGd0.12F4:Crx3+Er0.023+ (UCCr) material that is instead of ytterbium (Yb3+) ions. The UCCr material with a different concentration of Cr3+ ions (0≤x≤0.24) was synthesized by a facile hydrothermal synthesis method. The characterization of the developed UCCr material was performed by photoluminescence (PL), Field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD) and Electron paramagnetic resonance (EPR). The effect of Cr3+ ions on the upconversion luminescence and magnetic-resonant properties of UCCr material was investigated in detail. The upconversion mechanism was proposed.