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The crystallization behaviors of As-Se-Bi chalcogenide glasses were investigated by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Three models were used to study the glass transition behavior and the activation energy. Results showed thermal stability of glass against crystallization decreased with Bi addition in As-Se-Bi system. The mechanism of crystal growth in glasses was also studied by the Avrami exponent n. For B0, B2.5 and B5, n values are 3.12, 1.59, and 2.21 (low temperature) and 4.61 (high temperature), respectively. The thermal stability of glass is in good agreement with glass network structure. It was found that glass network structures closely associated with the Bi content and As/Se ratio were studied by X-ray diffraction and Raman spectroscopy. And the different ratios lead to the change of Bi2Se3 crystalline orientation. This article is protected by copyright. All rights reserved.

Alkali-free glasses have attracted tremendous attentions for their high glass transition temperature (Tg). Such a feature broadens their potential applications, especially in the area of high-density and high-power laser glasses. BaO–P2O5 glasses, as one of the major matrix materials due to its high-Tg, can be applied in high-power laser glasses. Introducing SiO2 is an effective method to improve the thermal, refractive index, and mechanical properties of phosphate glasses. Herein, we studied the barium silicophosphate glasses with MAS NMR and the Tg was successfully calculated by the topological constraint theory. The designed glass (20BaO–26.7SiO2–53.3P2O5, mol%) with a high Tg (789K) was prepared and it also exhibited high refractive index and high Vickers hardness, suggesting the barium silicophosphate glasses have widespread applications in high-power laser glasses and optical fibers.

Since 2012, zinc gallogermanate has drawn interests as an excellent host phosphor for a variety of dopants (e.g., Cr3+, Bi3+ and Mn2+). However, the origin of its self-activated luminescence has been largely unknown. Here, zinc gallogermanate of the composition Zn1+xGa2−2xGexO4 (0 ≤ x ≤ 1) is prepared by solid-state reaction, and the evolution of the crystal structure with the composition is studied. The phosphors show a broad white-bluish emission upon excitation by ultraviolet (UV) light, and the luminescence intensity greatly increases as Ga3+ are substituted by Ge4+. A full spectrum of the defects and trap centers responsible for the luminescence is given by a multiple characterization methods, such as low temperature electron spin resonance, positron annihilation lifetime and thermoluminescence spectra. The results show that the zinc gallogermanate is a promising self-activated phosphor for a variety of applications.

In this article, Ta5+ ion doped P2O5–ZnO–ZnSO4–Na2O glasses were prepared. Luminescence properties of Ta5+ doped sulfophosphate glass-ceramics were studied. A broad blue emission band of Ta5+ doped sulfaphosphate glass excited by 254 nm Ultraviolet (UV) light was observed at the range 350–600 nm. After thermal treatment, the luminescence intensity of Ta5+ doped glass-ceramic was significantly enhanced by over 400%. More importantly, the luminescence intensity could be fine-tuned by controlling the matrix crystallinity surrounding the Ta5+ cations, which was achieved via a facile heat treatment. Compared with the glass samples, the decay life of Ta5+ doped glass-ceramics became shorter and two different decay times were calculated based on a second-order exponential decay model. This indicates that Ta5+ cations properly exist around NaZnPO4 crystallite in the residual glass phase.

Solid state electric field-assisted diffusion has been widely applied to oxide glasses to make buried waveguides but rarely employed in chalcogenide glasses. We have previously fabricated Ag-doped Ge20Ga5Sb10S65 glasses by electric fieldassisted diffusion and studied the Ag + concentration profiles. However, the optical properties after the silver diffusion were left unexplored. In this article, we use the “scratch method” by atomic force microscopy to investigate the refractive index profile of Dy 3+ -doped Ge20Ga5Sb10S65 glass after the silver diffusion. The refractive index profile obtained after the diffusion is very symmetric. An enhanced Dy 3+ 1.34lm emission has been found only in the presence of silver. The product of measured lifetime and emission cross-section (τmeaσe) is increased by 12% after the diffusion.

On the basis of the glass network structure and spectroscopy information, the full-color-emitting borophosphate glasses doped/codoped with Eu2+ and Mn2+ ions were synthesized, and their photoluminescence (PL) properties were evaluated. The interaction of Mn2+–Mn2+ pairs shifts its emission to longer wavelength without a notable negative effect on the intensity in Mn2+-doped glasses. Depending on the small amount of B2O3 added, the Mn2+ ions suffer different surrounding environments giving three emission bands at 526, 597, and 638 nm, respectively. In codoped samples, the weak red emission resulting from the forbidden transition of Mn2+ could be enhanced by the energy transfer from Eu2+ because of the spectral overlap between the PL excitation spectrum of Mn2+ and the PL spectrum of Eu2+. The energy transfer process was confirmed by the luminescence spectra, transmittance spectra, and the calculation of energy transfer efficiency of the glasses. Meanwhile, the potential mechanism of energy transfer is evident to be dipole–dipole interaction. Finally, the Eu2+–Mn2+-codoped borophosphate glasses showed an adjustable full-color emission that could be regarded as a good candidate for ultraviolet light-emitting diode (LED) chip-based white LEDs.

In the present work, barium phosphate glasses codoped with Dy3+–Eu3+ ions are prepared and their photoluminescence properties are studied by the excitation and emission spectra. The dependence of emission spectra on the concentrations of Eu3+ and Dy3+ is discussed with respect to the energy transfer (ET) process from Dy3+ to Eu3+ ions and relevant ET mechanism was proposed.

Luminescence behaviors of Ce 3+ ions in GeS 2 ―Ga 2 S 3 ―CsCl chalcohalide glasses are reported for the first time. The dependence of Ce 3+ concentration and host composition on absorption and photoluminescence spectra are investigated. Results show that these glasses exhibit broadband emission from 470 to 600 nm under a blue excitation. Luminescence intensity is enhanced with the increasing of Ce 3+ ions and reaches the maximum at 0.08 mol%. The decrease of CsCl content results in the red shift of absorption cut-off edge and emission band, and decreased luminescence intensity. The mechanism for these phenomena is discussed with the theory of optical basicity.

Notably enhanced Mn2+ yellow emission is observed in CsCl modified and Eu2+/Mn2+ codoped Ge–Ga–S glasses under near-ultraviolet (NUV) excitation. The plausible efficiency of energy transfer (ET) from Eu2+ to Mn2+ is as high as 91%, which is obtained by measurement of luminescence decay of Eu2+ in samples doped with and without Mn2+. The Eu2+/Mn2+ codoping significantly increases the excitation cross section at the NUV region, which is at heart of the enhanced Mn2+ yellow emission. The ET processes responsible for the enhanced luminescence are discussed.

We report on photoluminescence from Mn2+-doped chalcohalide glasses of the GeS2–Ga2S3–CsCl system. Upon blue excitation at 447 nm, a broad emission band occurs in the green spectral range from 500 to 600 nm, indicating the presence of tetrahedrally coordinated Mn2+ species. When the Mn2+-concentration is increased up to 2 mol%, an increasingly intense secondary emission band evolves at about 610–660 nm. Meanwhile, the intensity of the green band decreases gradually and shifts toward the red, resulting a very flatten luminescence from 500 to 750 nm, which provides a promising white light emitting source. As for the origin of this unique luminescence behavior of Mn2+, it is proposed that the ligand coordination number of Mn2+ in the present chalcohalide glasses experiences a partial change from tetrahedral to octahedral coordination.

Tb3+–Mn2+-codoped zinc–strontium–phosphate glasses are prepared by the conventional melt-quenching method, and their photoluminescence spectroscopy is investigated as a function of the Mn2+ concentration. It is observed that the excitation band at 350 nm due to Tb3+ overlaps that of Mn2+ ions, thus suitable for efficiently activating Tb3+–Mn2+-codoped glasses. The emission spectra of codoped glasses simultaneously show the blue (486 nm), green (541 and 582 nm), and red (617 nm) emissions. The 590 nm broad emissions of Mn2+ ions have been enhanced with the doping of Tb3+ ions, while the Tb3+ emissions have decreased with the increasing concentration of Mn2+. Decay curves of Tb3+ ions with the different concentrations of Mn2+ ions are also studied. The possible energy transfer process from Tb3+ to Mn2+ ions is proposed and the relevant mechanism is discussed.