Luminescence spectra of Eu3+-doped GeO2-PbO-Bi2O3 glasses

Europium-doped germanium-lead bismuth based glasses in the chemical composition of 62GeO(2)- (13-X) PbO-25Bi(2)O(3)-XEu2O3 (where X = 0.1, 0.2, 0.5, 1.0, and 1.5 mol%) have been prepared and carried out in a systematic study on their emission spectra. Upon exposure to the UV source (200-270 nm) these glasses have shown bright reddish orange phosphorescent color that lasted for about half an hour. From the measured glass refractive index (n(d) = 1.871) and density (5.965 g.cm(-3)), glass reflectivity, number of luminescent ions (N-eu(3+)), and inter ionic distance (r(eu-eu)) values of these europium glasses have been computed. The PL spectra of these glasses have shown emission transitions (D-5(0)--> F-7(1,2,3&4)) at 593, 612, 652, and 697 nm. We have examined the dependence of the emission spectra and decay curves on the excitation wavelengths at 228, 246, 259, 361, and 393 nm from a Xe source. Decay curves of the emission transitions have been characterized by a double exponential fitting procedure. From the photoluminescence spectra, concentration quenching at the values of the dopant ion content above 1.0 mol% has been noticed. (C) 2001 Elsevier Science Ltd. All rights reserved.