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The visible-to-ultraviolet upconversion in Pr3+:Y2SiO5 crystals have been investigated at room temperature for three different Pr3+ ion concentrations. The upconverted luminescence bands at the UV region from 270 to 350 nm were obtained with visible laser excitation. The upconversion mechanism was studied by observing the absorption and excitation spectra, the dependence of upconverted luminescenc
