980Â nm upconversion luminescence from oxy-fluoride glasses and glass-ceramics doped with Yb3Â +and Er3Â + ions

Infrared upconversion luminescence properties of Er3 +/Yb3 + co-doped oxy-fluoride glasses and glass-ceramics were investigated. Under 1550 nm laser excitation, infrared emission centered at ~ 980 nm that originated from the Yb3 +: 2F5/2 → 2F7/2 and Er3 +: 4I11/2 → 4F15/2 transitions was observed. The upconversion luminescence was enhanced both by Yb3 + content increase and by precipitation of β-PbF2 nano-crystals in the glass matrix. The energy transfer process between Yb3 + and Er3 + ions dominated IR upconversion emission, and Yb3 + can be used as energy acceptor. The strong upconverted luminescence can be used to increase the efficiency of silicon solar cells.