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The formation mechanism of Cd–S–Se quantum dots (QDs) with a CdS/CdSe core–shell structure within a silicate glass system was investigated by monitoring the change in the first excitonic absorption peak of CdSe, CdS, and Cd–S–Se QDs as a function of the heat‐treatment (HT) duration. When a silicate glass containing QD formation components for CdSe or CdS single‐phased QDs was heat‐treated, CdSe QDs grew via Ostwald ripening, whereas CdS QDs hardly formed within the given silicate glass matrix. When the glass, including CdO, ZnSe, and ZnS, was utilized for the synthesis of Cd–S–Se QDs within the glass matrix, Cd–S–Se QDs were successfully formed and exhibited similar growth behavior to CdSe QDs during the initial stage of HT. The structural changes in the QD‐embedded glasses during HT were also monitored by Raman spectroscopy and discussed, and a possible formation mechanism of CdSe/CdS core–shell‐structured QDs within silicate glasses is suggested. [ABSTRACT FROM AUTHOR]

Quantum dot embedded glasses (QDEGs) were prepared by the conventional melt‐quenching method to enhance its color conversion efficiency via optimizing the concentration of ZnS, ZnSe, and CdO within the silicate‐based glass matrix. The QDEG, which contained 0.875 ZnS, 0.625 ZnSe, and 0.75 CdO (in mol%) and was heat treated at 500°C for 10 hours showed promising color conversion with an improved quantum yield of up to 25%. Color coordination of light‐emitting diodes (LEDs) mounted with the QDEGs could be adjusted by tuning heat‐treatment conditions and thickness control of QDEGs. The practical feasibility of the QDEG for a white LED is demonstrated with a reasonable glass thickness for LED packaging process. The formation of Cd‐S‐Se quantum dots within a glass matrix was identified by Raman and HR‐TEM analyses. The effect of ZnSe and CdO on the formation of Cd‐S‐Se quantum dots within silicate glass is also discussed. [ABSTRACT FROM AUTHOR]

Abstract: Glasses with a P2O5–SnO–MnO ternary system were synthesized and characterized. Glass forming range was determined to be 5–20mol% of MnO when the content of SnO was kept below 50mol%. Various analyses including thermal, optical and structural characterization were performed on (85− x)P2O5–xSnO–15MnO (x =30, 35, 40 and 45 in mol%) and (55− y)P2O5–45SnO–yMnO (y =0, 5, 10 and 15 in mol%) glasses in order to investigate the compositional effect of SnO and MnO on the properties of glass. Glass transition temperature of all the prepared glass samples turned out to be below 350°C, but showed a compositional dependency on SnO and MnO, which was discussed in terms of the structural changes derived from Raman spectroscopy. The visible transparency of both glass series was identified with their high optical bandgap of 3.4–3.7eV and their refractive indices varied between 1.6 and 1.9 depending on the wavelength monitored and composition. Er3+ doped the glasses to examine their potential as a photonic gain medium. Radiative emission properties, Judd–Ofelt analysis and stimulated emission cross-sections also exhibited the influence of SnO and MnO and suggested the preferred concentrations of SnO and MnO as 35mol% and 5mol%, respectively. Modification of the local structure around the Er3+-ion upon the compositional variation was responsible for the phenomena. This is also discussed with the structural contribution of SnO and MnO. [ABSTRACT FROM AUTHOR]

Glass-forming range and electrical conduction properties of V2O5–P2O5–WO3 ternary system were investigated. The glass-forming ability of this system was quite good within a wide compositional area where the P2O5 content ranges from 20 to 80 mol%. This glass exhibited a high dc-conductivity up to 6.71 × 10−4Ω/cm at 473 K. The variation of conductivity (log(σ T)) of the glass with temperature (1/ T) exhibited a linear relationship, which suggests electrical conduction through the small polaron hopping above room temperature. Compositional effect on the conductivity was studied upon varying WO3 and P2O5 concentration. Substitution of V2O5 with P2O5 resulted in a decrease of the conductivity with the increase of activation energy, while substitution of WO3 showed relatively little effect on the activation energy. Structural modification along with the valence state change of vanadium and tungsten ions were discussed in connection with Raman spectroscopy and X-ray photoelectron spectroscopy analysis. [ABSTRACT FROM AUTHOR]

High-refractive index glasses are used to produce glass lenses by the precision optical Glass Mold Press (GMP) process and have been extensively studied because of increased demand for their application in telecommunications, optical lenses, and cameras. Borate glasses containing Ta 2 O 5 , Nb 2 O 5 , La 2 O 3 and Gd 2 O 3 have mainly been used as materials for GMP because of their excellent optical properties and low production cost. This study conducted a systematic investigation of the B 2 O 3 –La 2 O 3 –Ta 2 O 5 –SiO 2 quaternary glass system for precision GMP applications. The glass forming range of the quaternary system was studied using (B 2 O 3 +SiO 2)–La 2 O 3 –Ta 2 O 5 and changes in physical and thermal properties such as refractive index, density and glass transition temperature of the obtained glasses were examined. Compositional dependent structural changes were also inspected by Raman spectroscopy and solid state nuclear magnetic resonance (NMR) analyses, to determine the compositions' effect on thermal and optical properties. [ABSTRACT FROM AUTHOR]

Abstract: We experimentally verify that a color center in the form of takes shape in silicate glasses containing relatively small amount of ZnSe which are prepared via a conventional melt-quenching process. Samples also produce broad photoluminescence when excited with UV light source, suggesting potential applications in the visible range. Analyses based on X-ray diffraction patterns, high resolution transmission electron microscopy, and Raman spectroscopy support the formation of color centers in addition to Se nanocrystals. [Copyright &y& Elsevier]

• Aluminosilicate glasses varying P 2 O 5 and B 2 O 3 were chemically strengthened. • Compressive stress and depth of layer were varied with P 2 O 5 and B 2 O 3 content. • Interdiffusion coefficient was increased with P 2 O 5 and decreased with B 2 O 3. • Modification of glass structure by P 2 O 5 and B 2 O 3 was responsible for the change. Sodium alumino-silicate (SAS) glasses were synthesized with varying P 2 O 5 and B 2 O 3 contents, and their effect on chemical strengthening properties such as surface compressive stress (CS) and depth of layer (DOL) was examined. When P 2 O 5 replaced SiO 2 , CS decreased, while DOL increased with P 2 O 5 content. In contrast, B 2 O 3 improved CS at the expense of DOL. The simultaneous addition of P 2 O 5 and B 2 O 3 with varying ratios also changed CS and DOL depending on the P 2 O 5 and B 2 O 3 content. The interdiffusion coefficients of K+ ions in SAS glasses were estimated using the Boltzmann–Matano equation and supported the observed effects of P 2 O 5 and B 2 O 3. Structural modifications related to changes in chemical strengthening properties were monitored by Raman spectroscopy and discussed. [ABSTRACT FROM AUTHOR]