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

Europium-doped germanium-lead bismuth based glasses in the chemical composition of 62GeO2-(13-X) PbO-25Bi2O3-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 (nd = 1.871) and density (5.965 g·cm−3), glass reflectivity, number of luminescent ions (Neu3+), and inter ionic distance (reu-eu) values of these europium glasses have been computed. The PL spectra of these glasses have shown emission transitions (5D0→7F1,2,3&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.