Efficient blue-to-UV-B up-conversion in Li2CaSiO4:Pr,Gd,Na

The present work concerns the efficient blue-to-UV-B up-conversion in the host material Li 2 CaSiO 4 by co-doping with Pr 3+ and Gd 3+ . The focus is on excitation with a 488 nm laser diode, which initiates a multi-stage energy transfer process resulting in intense emission in the UV-B range at 311 nm. The maximum emission intensity was observed at a Gd 3+ doping level of 10 mol%. The spectral analyses demonstrate an efficient, non-radiative energy transfer from the Pr 3+ to the Gd 3+ ion as the central mechanism of this process. The up-conversion emission achieved is primarily based on a two-photon process, which is triggered particularly effectively by the high-power density of the laser light. These results emphasise the potential of the investigated materials for applications in photomedical therapy and UV-based disinfection, where compact laser systems can be used. • Investigation into the photoluminescence of the solid solution Li 2 Ca 1-2x Pr 0.01 Gd x Na 0.1+x SiO 4 (with x = 0.001 – 0.1). • Photoluminescence spectra of Li 2 Ca 1-2x Pr 0.01 Gd x Na 0.1+x SiO 4 • Enhancement of the Up-conversion efficiency with a co-doping level of 1 % Pr 3+ and 10 % Gd 3+