Silver doping of silica-hafnia waveguides containing Tb3+/Yb3+ rare earths for downconversion in PV solar cells

• Published in: Optical materials 2016-10, Vol.60, p.264-269
• Main Authors: Enrichi, F., Armellini, C., Battaglin, G., Belluomo, F., Belmokhtar, S., Bouajaj, A., Cattaruzza, E., Ferrari, M., Gonella, F., Lukowiak, A., Mardegan, M., Polizzi, S., Pontoglio, E., Righini, G.C., Sada, C., Trave, E., Zur, L.
• Format: Article
• Language: English
• Subjects: Ag doping; Downconversion; Experimental Physics; Experimentell fysik; Optical waveguides; Photoluminescence; Solar cells; Tb[sbnd]Yb rare earths
• ISSN: 0925-3467; 1873-1252; 1873-1252
• DOI: 10.1016/j.optmat.2016.07.048

The aim of this paper is to study the possibility to obtain an efficient downconverting waveguide which combines the quantum cutting properties of Tb3+/Yb3+ codoped materials with the optical sensitizing effects provided by silver doping. The preparation of 70SiO2–30HfO2 glass and glass-ceramic waveguides by sol-gel route, followed by Ag doping by immersion in molten salt bath is reported. The films were subsequently annealed in air to induce the migration and/or aggregation of the metal ions. Results of compositional and optical characterization are given, providing evidence for the successful introduction of Ag in the films, while the photoluminescence emission is strongly dependent on the annealing conditions. These films could find potential applications as downshifting layers to increase the efficiency of PV solar cells. Photoluminescence excitation (left) and emission (right) for Tb(1%)-Yb(4%) codoped glass waveguides before (TY-G) and after Ag introduction (TY-G-A), and after further annealing at 380 °C (TY-G-B) or 440 °C (TY-G-C) for 1 h. [Display omitted] •By immersion in molten salt bath, Ag can be introduced in Tb3+/Yb3+ codoped silica-hafnia glass waveguides.•Intense photoluminescence emission is observed after Ag introduction in the glass samples.•Efficient UV absorption followed by blue emission can make the samples suitable as downshifting layers in solar cells.