Synthesis, morphology and optical properties of the luminescent phosphate-molybdate glasses of the P2O5-MoO3-Bi2O3-K2O-EuPO4 system

The study deals with synthesis, structure and optical properties of the phosphate glasses of the composition (1-x) *(44.37P2O5 - 8.32MoO3 -2.94Bi2O3 - 44.37K2O) - xEuPO4 (where x = 0, 0.5, 1.0, 2.0, and 5.0 mol. %). The structure, morphology, and optical properties of the glasses have been observed and analyzed with the use of the XRD, SEM, light diffuse reflection, and luminescent methods. It was found that the glasses doped with EuPO4 crystalline particles reveal intensive photoluminescence mainly caused by the 5D0->7FJ (J = 1 – 4) radiation transitions in the Eu3+ ions. Molybdenum (VI) and bismuth (III) oxides modify a vitreous network and can provide wide light absorption bands in the spectral range ~300 – 430 nm and low intensity luminescence bands in the range 300 – 525 nm, too. Based on a comparison of the spectral characteristics of the radiation of Eu3+ ions luminescence in EuPO4 crystals and manufactured glasses, it was assumed that the initial EuPO4 particles do not dissolve completely under melting and are present in the manufactured glasses as nanoparticles of small (several nanometers) size. The obtained results indicates that the glasses under study can be used for elaboration of “warm light” emitting devices.