Structural and optical studies of aluminosilicate films doped with (Tb3+, Er3+)/Yb3+ by ion implantation

Harvesting solar energy demands efficient solar cells working over the largest region of the solar spectrum possible. The extension of the wavelength region is viable through the use of frequency converting phosphors. Rare earth (RE) pairs fulfill this criterion and in particular the Erbium/Ytterbium pair allows a good coverage from the near-infrared (NIR) to visible by up conversion (UC) at room temperature. In this study we report the structural and optical properties of aluminosilicate glass films grown by sol-gel (SG) spin-coating deposition technique and co-doped with (Er, Tb)/Yb by ion implantation with different fluences and energy. After implantation, the films were annealed at 1000 °C for 20 min and characterized by scanning electron microscopy (SEM), Rutherford Backscattering (RBS), X-ray diffraction (XRD) and Photoluminescence (PL). The annealing induces a significant redistribution of the RE ions in the films. In particular, the samples implanted with Tb + Yb show a tendency to form a homogeneous distribution over the entire film. In both cases PL shows the cooperative up conversion process.