Enhanced up-converted fluorescence in fluorozirconate based glass ceramics for high efficiency solar cells

Thermal processing of as-made fluorozirconate glasses which were additionally doped with neodymium and chlorine ions leads to enhanced up-conversion fluorescence intensities in these glass ceramics. The samples were annealed between 240°C and 290°C while the optimum value was found for the 270°C sample. We investigated the power dependence of the infrared fluorescence, the 2-photon up-conversion, and the 3-photon up-conversion fluorescence intensities as well as the corresponding radiative lifetimes. In analogy to the up-conversion intensity, the radiative lifetime of the Nd3+ fluorescence at about 880 nm depends significantly on the annealing temperature: the longest lifetime was observed for the 270°C sample.