Enabling Yb3+ Luminescence with Visible Light Response in Mg2GeO4 via Energy Transfer

Thegrowing demand for spectroscopy applications in the areas ofbioimaging, food quality analysis, and temperature sensing has ledto extensive research on infrared light sources. It is crucial forthe design of cost-effective and high-performance systems that phosphorspossess the ability to absorb blue light from commercial LEDs andconvert the excitation energy to long-wavelength infrared luminescence.In this work, we obtained Yb3+ luminescence with visiblelight response by utilizing the energy transfer from Cr3+ to Yb3+ in Mg2GeO4. After the introductionof Yb3+, intense NIR luminescence peaking at 974 nm canbe achieved with an increasing intensity. The local structure analysiswas performed to investigate the preferential occupation of Yb3+ ions and the energy transfer process in Mg2GeO4. Considering the properties of thermally coupled anti-Stokesand Stokes emissions of Yb3+ and the sensitive variationof the emission intensity, the potential application of Mg2GeO4:Cr3+, Yb3+ as thermometerswas demonstrated. The near-infrared(NIR) luminescence properties of Mg2GeO4:Cr3+/Yb3+ phosphor isreported. By efficient energy transfer from Cr3+ to Yb3+, intense NIR luminescence peaking at 974 nm with severalside bands can be achieved. The peak intensity and integrated intensityafter doping increase by 13.31 and 2.64 times compared with thoseof the Cr3+ single-doped sample.