Rare earth ions and Ag nanoaggregates in silica-hafnia sol gel films: broadband downshifting materials for solar cells.

Enrichi F., Battaglin G., Belluomo F., Cattaruzza E., Coccetti F., Ferrari M., Gonella F., Mardegan M., Martucci A., Pelli S., Quandt A., Trave E., Zur L., Righini G.C.
  Mercoledì 28/09   16:30 - 19:00   Edificio Psicologia 2 - Aula 2B   II - Fisica della materia
Energy harvesting in solar cells may be improved by spectral conversion layers, to convert poorly absorbed frequencies of the solar spectrum into the region of maximum absorption of the cell. To this purpose, we report the realization of efficient downconverting silica-hafnia glassy or glass-ceramic waveguides which combine the spectral properties of rare-earth--doped materials with the optical sensitizing effects of Ag nanoaggregates. The films were prepared by sol-gel route, followed by Ag ion-exchange and annealing. Structural and optical characterizations demonstrated broadband downshifting properties, with potential applications to increase the efficiency of PV solar cells.