Nanocomposites and nanomaterials

Effect of metal oxides on structure and properties of   
borate -phosphate glasses
Nedilko S.G.1, Scherbatskii V.P.1, Stus N.V.1, Yaschuk V.P.1, Gomenyuk O.V.2, Sheludko V.I.2, Androulidaki M.1, Manousaki A.1, 
Papadopoulos A.3, Stratacis M.3 
1 Taras Shevchenko National University of Kyiv. Volodymyrska st., 64/13, Kyiv-01601, Ukraine 
E-mail: snedilko@univ.kiev.ua
2 O. Dovzhenko Hlukhiv National Pedagogical University, Hlukhiv, Ukraine
3 Institute of Electronic Structure & Laser (IESL) of Foundation for Research & Technology Hellas (FORTH), Heraklion 711 10 Crete, Greece

Materials and composites, which possess luminescent properties, have various fields of application: industry, science and technology, everyday life, etc. Some of them now are developed for advanced opto-electronic devices, white light-emitting diodes (WLED) and solar cells. 
The series of glasses with compositions of the common formulae mNa2O - nB2O3 -kP2O5 : xMO - yRE (M = Mn, Zn, Ge, Pb; RE = Eu, Pr) were prepared and studied by us. The molar composition of alkali phosphate-borate glass-forming matrix was close to 40% Na2O - 20% P2O5 -40 % B2O3. The amount of the Mn, Zn,Ge or Pb was in the range of 1 – 25 mol%, while the RE ions content was 1 – 5 mas %. All the samples were made by the melt-quenching procedure and we have found that melting temperature depends mainly on the m/n/k ratio, while amount of the Mn, Zn,Ge or Pb influences microstructure and quality of the glasses.
The glasses were characterized by SEM, XRD, DTA, IR- and UV-VIS spectroscopy, and their luminescent properties were studied too. Lluminescence spectra are complex and they range from 400 up to 750 nm. Luminescence kinetic is complex, and decay time differs for different spectral components. The glasses doped with RE also showed the luminescence caused by radiation transitions in the f-f shell of the RE ions. The luminescence spectra of such samples are the superposition of the wide bands related with luminescence of the glass matrix and linear spectra caused by intrinsic radiation transitions in the RE ions.
The conclusion was made that glasses of mentioned compositions can be suitable for development of glass - ceramic luminescent coatings for WLEDs and other devices.