EFFECT OF OXIDE ADDITIVES ON UP-CONVERSION LUMINESCENCE OF ERBIUM IONS IN ALKALINE GERMANATE GLASSES

The effect of additives in sodium germanate glass on the up-conversion luminescence of an erbium ion was studied. Samples of glasses were prepared by high-temperature synthesis in corundum crucible. Synthesis temperature was 1250 °С. Synthesized glass had a composition of 58,95GeO2–27,79Na2O–8,67Yb2O3–4,34LaO–0,25Er2O3 mol% with additives of 5 mol% of the following oxides: Al2O3, Nb2O5, SiO2, BaO, TiO2, PbO, P2O5, MgO. Up-conversion luminescence spectra were recorded in the wavelength range from 450 to 700 nm when excited by a semiconductor laser at 975 nm. Three bands were identified on the luminescence spectra corresponding to radiative transitions of the erbium ion 2H11/2→4I15/2 with maximum of about 520 nm; 4S3/2→4I15/2 with maximum of 550 nm and 4F9/2→4I15/2 with maximum of 670 nm. The luminescent properties of the glass with additives were compared to those of the initial glass. The effect of additives on the relative intensity redistribution of upconversion luminescence was shown. Compared to the red luminescence band (4F9/2→4I15/2), the green band (2H11/2→4I15/2) intensity is a maximum for glass with the addition of phosphorus oxide; glass with the addition of lead oxide has the minimum intensity. The obtained dependence of the relative intensities of the up-conversion luminescence bands on the glass composition can find practical application in the development of optical luminescent sensors, as well as up-converters for solar cells.