Up-conversion emission in KGd(WO 4) 2 single crystals triply-doped with Er 3+/Yb 3+/Tm 3+, Tb 3+/Yb 3+/Tm 3+ and Pr 3+/Yb 3+/Tm 3+ ions

Abstract

Triply-doped single crystals KGd(WO 4) 2:Er 3+/Yb 3+/Tm 3+, KGd(WO 4) 2:Tb 3+/Yb 3+/Tm 3+ and KGd(WO 4) 2:Pr 3+/Yb 3+/Tm 3+ were grown by the Top Seeded Solution Growth (TSSG) method, with an aim of getting efficient up-converted multicolored luminescence, which subsequently can be used for generation of white light. Such an aim determined the choice of the triply doped compounds: excitation of the Yb 3+ ions in the infrared spectral region is followed by red, green and blue emission from other dopants. It was shown that all these systems exhibit multicolor up-conversion fluorescence under 980 nm laser irradiation. Detailed spectroscopic studies of their absorption and luminescence spectra were performed. From the analysis of the dependence of the intensity of fluorescence on the excitation power the conclusion was made about significant role played by the host’s conduction band and other possible defects of the KGd(WO 4) 2 crystal lattice in the up-conversion processes.