Up-conversion and near infrared luminescence in Er3+/Yb3+ co-doped glass-ceramic containing MgGa2O4 nano-crystals

The MgO-Ga2O3-SiO2 (MG-S) glasses and nanocrystalline glass-ceramics (GCs) containing MgGa2O4 nanocrystals codoped with Er3+ and Yb3+ were prepared by a simple sol-gel method. The formation of MgGa2O4 nanocrystals in the GCs was confirmed by the X-ray diffraction (XRD). Their morphology was investigated applying high-resolution transmission electron microscopy (HRTEM). Stark splitting of near infrared (NIR) and up-conversion (UC) emission implies that the Er3+ is incorporated into MgGa2O4 nanocrystals. The effect of the MgO, Ga2O3 content and sintering temperature on the structure of the prepared samples was systematically studied. Under 980 nm excitation, intense UC and NIR emission (1530 nm) were observed in the MG-S GCs by efficient energy transfer from Yb3+ to Er3+. The two-photon process was confirmed to be responsible for both the green and red UC emissions.