Doped Glass Compositions Research Articles

Synthesis and characterization of Eu3+-doped glass ceramics from the system CaO-GeO2-Li2O-B2O3

Three Eu3+ doped glass compositions from the system CaO-GeO2-Li2O-B2O3 were thermally treated for obtaining of the nano glass-ceramics. A series of glass ceramics were obtained under different heat treatment conditions for each glass composition. The main crystallizing phases in the three investigated compositions were Ca2GeO4, Ca5Ge3O11 or Li2CaGeO4. Research was aimed at finding the optimal thermal treatment conditions of parent glasses for preparing of glass-ceramics with optimal particle size, degree of crystallization and transparency determining high emission intensity. For this, a stepwise heat treatment was applied to obtain a series of glass-ceramic samples from the same starting glass composition. Under such treatment, the kinetics of nucleation and growth of the crystallizing phase were tracked. DTA, XRD, TEM, UV–vis analyses were used for characterization of the obtained series of glass-ceramics. Based on the results, it was concluded that the main factors determining the behavior of the crystallizing nanophase (predominant new nucleation or predominant growth of already appeared seeds) are the thermal treatment conditions and the composition and structure of the parent glass, and not so much the composition and structure of the crystallizing phase.

Judd–Ofelt analysis of spectroscopic properties of Er3+ doped TeO2-BaO-ZnO glasses

UV-NIR Absorption spectra of the glass system 0.6TeO2 - (0.35-y)BaO - 0.05ZnO - yEr2O3 (where y = 0.01, 0.025, 0.035, 0.04 and 0.05 mol %), have been recorded in the range of 200–2500 nm. The Judd-Ofelt (J-O) parameters (Ωλ, λ = 2, 4, and 6) are calculated using the absorption bands of the doped glass compositions with y mol % content of Er2O3. The radiative properties of the Er3+ ions are calculated using J-O parameters. Other parameters such as; oscillator strength, radiative lifetime, transition probabilities, spectroscopic quality and branching ratio of several excited states of the Er3+ ions are calculated. All spectra were resolved using the normalized area method. Then, the emission from the lowest and upper Stark levels of the 4I13/2 state and the gain cross-section of the laser transition level from 4I13/2 → 4I15/2 are obtained. Results of the spectroscopic properties revealed that these glasses doped with Er3+ are promising candidates for optical applications.

Optical Properties of Ag Nanoparticle-Glass Composites

Silver nanoparticles doped glass composites were prepared by ion-exchange and subsequent thermal treatment processes. The optical properties of silver nanoparticle-glass composites were investigated by UV-VIS spectrophotometer and z-scan technique. The results show that the optimal Ag+/Na+ ion-exchange temperature range is between 310°C and 380°C, higher ion-exchange temperature or higher AgNO3 concentration in melt or longer ion-exchange period favors the introduction of more Ag+ ions into soda lime silicate glasses. The higher Ag+ concentration introduced into silicate glass, the larger the volume fraction of Ag nanoparticles in glass after annealing will be. Ag nanoparticles size and volume fraction become larger with increasing the annealing temperature and extending the annealing time. The off-resonant third-order nonlinear optical susceptibility of Ag nanoparticle-glass composite exhibits a value of 1.16×10-10esu where the real part is -1.15×10-10esu, and imaginary part is 1.4×10-11esu.

Porous silicon – rare earth doped xerogel and glass composites

AbstractThe development of components for photonics applications is growing exponentially. The sol–gel method is now recognised as a convenient and flexible way to deposit oxide or glass films on a variety of hosts, including porous silicon. In the present work we incorporated erbium and europium doped xerogel into porous silicon and developed new porous silicon – rare earth doped glass composites. Various characteris‐ation techniques including FTIR, Raman Spectroscopy, Thermal Gravimetric Analysis and Scanning Electron Microscopy were employed in this work. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)