In this report the optical properties and energy-transfer frequency upconversion luminescence of Er3+/Yb3+-codoped
laponite-derived powders under 975 nm infrared excitation is investigated. The 75%(laponite):25%(PbF2) samples
doped with erbium and ytterbium ions, generated high intensity red emission around 660 nm and lower intensity green
emission around 525, and 545 nm. The observed emission signals were examined as a function of the excitation power
and annealing temperature. The results indicate that energy-transfer, and excited-state absorption are the major
upconversion excitation mechanism for the erbium excited-state red emitting level. The precursor glass samples were
also heat treated at annealing temperatures of 300 °C, 400 °C, 500 °C, and 600 °C, for a 2h period. The dependence of
the visible upconversion luminescence emission upon the annealing temperature indicated the existence of an optimum
temperature which leads to the generation of the most intense and spectrally pure red emission signal.
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