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Te-based glasses are ideal material for life detection and infrared-sensing applications because of their excellent far-infrared properties. In this study, the influence of Ag- and AgI- doped Te-based glasses were discussed. Thermal and optical properties of the prepared glasses were evaluated using X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopy. Results show that these glass samples have good amorphous state and thermal stability. However, Ge–Ga–Te–Ag and Ge–Ga–Te–AgI glass systems exhibit completely different in optical properties. With an increase of Ag content, the absorption cut-off edge of Ge–Ga–Te–Ag glass system has a red shift. On the contrary, a blue shift appears in Ge–Ga–Te–AgI glass system with an increase of AgI content. Moreover, the transmittance of Ge–Ga–Te–Ag glass system deteriorates while that of Ge–Ga–Te–AgI glass system ameliorates. All glass samples have wide infrared transmission windows and the far-infrared cut-off wavelengths of these glasses are beyond 25 μm. The main absorption peaks of these glasses are eliminated through a purifying method. [ABSTRACT FROM AUTHOR]

In this study, a novel Te-based glass system was investigated. Some properties of Ge–Ga–Te–NaI chalcogenide glasses such as physical, thermal and optical transmitting were discussed. XRD patterns show this glass system with best amorphous state can dissolve content of NaI as much as 35 at.%. The lowest cut-off wavelength of glass samples is 1645 nm which is the smallest wavelength among the reported Te-based glasses doping with halide. DSC curves indicate that all glass samples have good thermal stabilities (Δ T > 100 °C) and the highest Δ T value corresponding to (Ge 15 Ga 10 Te 75 ) 85 (NaI) 15 glass is 120 °C which is 8 °C greater than that of Ge–Ga–Te host glass. The infrared spectra manifest Ge–Ga–Te–NaI chalcogenide glass system has a wide infrared transmission window between 1.6 μm and 20 μm. Consequently, Ge–Ga–Te–NaI glasses can be a candidate material for far infrared optic imaging and bio-sensing applications. [ABSTRACT FROM AUTHOR]

Abstract: A serious of tellurium based chalcogenide glass were prepared and investigated. As it being transparent nearly up to 25μm and strong anti-hydrability, it becomes an optimized material for far-infrared application. Here, AgI was incorporated into the glasses acting as a glass modifier. With the help of AgI, a highest glass transition temperature, T g (151°C) can be obtained. Detailed physics and chemic properties of the glasses were analyzed with DTA and XRD. The infrared optical transmission spectra were studied with the help of FTIR and Raman test. A purifying process was adopted to eliminate the affections of impurities in the tellurium glass. These serious of glasses are all high transparent in the 8–20μm region, which fits for the applications of far-infrared optic imaging and sensing. [Copyright &y& Elsevier]

Abstract: A novel series of Ge–Te–BiI3 chalcogenide glasses were prepared by traditional melt-quenching method and the glass-forming region was determined. Properties measurements including density, Vis–NIR and infrared (IR) transmission spectra with FTIR, XRD, DSC were adopted to analyze the composition, structure and performance of the Ge–Te–BiI3 glass system. Based on the metallization criterion and band gap energy theory, the relationships between energy gap, metallization criterion and glass composition was investigated. The results show that with the addition of BiI3, the glasses-forming ability and thermal stability are improved. The values of energy band gap and metallization criterion are within the range of 0.627–0.343eV and 0.177–0.131, respectively. These series of glasses have wide optical transmission window from 2.2 to 25μm and can offer an alternative solution for far infrared transmitting applications. [Copyright &y& Elsevier]

Abstract: GeS2–In2S3–KI/AgI chalcohalide glasses were prepared by traditional melt-quenching method and the glass-forming region was determined. The dependence of glass properties on composition as formula of (100− x)(0.75GeS2–0.25In2S3)− x(In2S3–KI/AgI) was investigated. The allowed indirect transition of samples was calculated according to the classical Tauc equation. The results show that 50mol% AgI can be introduced in the glassy matrix while only 40mol% of KI can be incorporated in the GeS2–In2S3–KI glass system. GeS2–In2S3–AgI glass system has larger density, higher refractive index and better thermal stability, while GeS2–In2S3–KI glass system has shorter visible cut-off wavelength and higher optical band gap. [ABSTRACT FROM AUTHOR]

Abstract: A new family of Tellurium-based glasses GeTe4–Ga2Te3–AgX (X=I/Br/Cl) has been investigated and the glass-forming region was determined. Properties measurements include XRD, DTA, vis-NIR, and IR transmission spectra. The amorphous nature of the glasses has been proved by X-ray diffraction. Among the three systems, the GeTe4–Ga2Te3–AgI glass system shows superior glass-forming ability and thermal stability. The maximum value of ΔT (= T x − T g) lies at about 110°C for the glass composition 60GeTe4–2-20Ga2Te3–20AgI, while for 60GeTe4–20Ga2Te3–20AgBr and 60GeTe4–20Ga2Te3–20AgCl, the ΔT values are both only 88°C. Most of the studied glasses have a wide optical transmission window from 1.8 to 25μm. [ABSTRACT FROM AUTHOR]

Abstract: The glass-forming region of the GeSe2–In2Se3–KI system was reported firstly. The dependence of physical, thermal and optical properties on compositions as formula of (1− x)(0.8GeSe2–0.2In2Se3)–xKI (x =0, 0.1, 0.2, 0.3) chalcohalide glasses was investigated. The allowed direct transition and indirect transition, and Urbach energy of samples were calculated according to the classical Tauc equation. The results show that the glass system has good thermal stability and that there is an obvious blue-shift at the visible absorbing cutting-off edge. When the dissolved amount of KI increased from 0 to 30mol%, the direct optical band gap and the indirect optical band gap were in the range from 1.617 to 1.893eV and 1.573 to 1.857eV. With the decrease of the molar refraction the refractive index decreases, optical band gap and metallization criterion increase. The relationship between energy band gap and metallization criterion was analyzed and the optical properties of chalcohalide glasses were summarized. [Copyright &y& Elsevier]

In this study, a series of Ga-As-S glasses tailored by adding Ga as the host for Er 3 + ions were prepared and characterized. The effects of the introduction of Ga on the structure change and the Er 3 + middle infrared emission intensity have been studied by Raman scattering, X-ray diffraction and fluorescence spectra. The results show the incorporating of Ga into the As 2 S 3 glass induced the dissociation of [AsS 3/2 ] pyramids units in behalf of forming tetrahedral [GaS 4/2 ]. By adjusting the Ga content, this host can be doped up to 2 mol% Er 3 + without crystallization and concentration quenching effect. Besides, this system has very good thermal stability (ΔT > 230 °C) and strong broadband mid-infrared emission centered at 4700 nm, suggests that this system has the potential to be used as mid-infrared fiber material. [ABSTRACT FROM AUTHOR]

Nd 3+ was introduced into Er 3+ doped tellurite glass with composition of TeO 2 Nb 2 O 5 ZnO Na 2 O to improve the 2.7 μm band fluorescence upon the excitation of 800 nm LD. The DSC curve and Raman spectrum were measured to characterize the thermal stability and vibration nature of glass host. The absorption spectra, visible, near- and mid-infrared fluorescence emission spectra were measured to evaluate the effects of Nd 3+ introduction on the spectroscopic properties especially the 2.7 μm band fluorescence of Er 3+ . It is shown that the prepared tellurite glass exhibits a large glass transition temperature and no obvious crystallization peak is observed in the measured temperature range of 200–550 °C. Moreover, the introduction of Nd 3+ significantly improves the 2.7 μm band fluorescence intensity through joint energy transfer processes between the relevant excited levels of Er 3+ and Nd 3+ , and the energy transfer mechanisms are further investigated in detail by calculating energy transfer micro-parameters and efficiency. The excellent thermal stability and strong 2.7 μm fluorescence emission aroused by adopting codoping scheme indicate that the prepared Er 3+ /Nd 3+ codoped tellurite glass is a potential glass medium applied for the 2.7 μm mid-infrared band lasers. [ABSTRACT FROM AUTHOR]

Highlights: [•] Tm3+/Ho3+/Yb3+ codoped tellurite glasses were prepared using melt-quenching method. [•] The structure behavior, thermal stability and multicolor emission were investigated. [•] The thermal stability of prepared glass increased with rare-earth doped concentration. [•] The multicolor emission was demonstrated by adjusting rare-earth doped concentration. [•] The quantitative study of phonon-assisted energy transfer mechanism was presented. [ABSTRACT FROM AUTHOR]

Abstract: The Er3+/Tm3+ codoped WO3 modified tellurite glasses with molar composition of (75−x)TeO2–20ZnO–5Na2O–xWO3–0.2wt%Er2O3–0.8wt%Tm2O3 (x=0,4,8,12mol%) were prepared to realize the blue upconversion emission. The absorption spectra, visible upconversion spectra and 1.53µm band fluorescence spectra of glass samples were measured, together with the quantitative calculations of relevant spectroscopic parameters of Tm3+ and energy transfer micro-parameters between Er3+ and Tm3+ ions, to evaluate the effects of WO3 oxide on the spectroscopic properties of Er3+–Tm3+ ions. It was found that the introduction of WO3 oxide can further improve the blue upconversion emission of Tm3+ through an enhanced phonon-assisted energy transfer process. Meanwhile, with the increase of WO3 amount, the thermal stability of glass hosts, characterized by the difference between the glass crystallization onset temperature and the transition temperature which obtained from the measured differential scanning calorimeter (DSC) curves, increased and no obvious crystallization peak was detected when the WO3 amount increased to 12mol%. Furthermore, the glass structure was briefly analyzed with the obtained Judd–Ofelt intensity parameters, the measured Raman spectra and X-ray diffraction (XRD) curves. The present results demonstrate the feasibility of realizing strong blue upconversion emission by introducing WO3 oxide with high phonon energy into the Er3+/Tm3+ codoped tellurite glass and also indicate its potential application as a glass host applied for the blue upconversion lasers. [Copyright &y& Elsevier]

Highlights: [•] Er3+/Ce3+ co-doped tellurite glasses containing WO3 was prepared by a melt-quenching method. [•] 1.53μm Fluorescence properties and thermal stability were investigated. [•] Thermal stability of glass hosts increased with WO3 component. [•] 1.53μm Fluorescence intensity of Er3+ improved evidently with an enhanced phonon-assisted energy transfer. [•] The prepared glasses possess a large amplification quality factor of Er3+ at 1.53μm band. [Copyright &y& Elsevier]

Abstract: A systematic series of (Ge20Se15Te65)1− x –(SnI2) x (x =0, 0.05, 0.1, 0.15) chalcogenide glasses have been prepared. The amorphous nature can be confirmed by XRD and SEM. With the SnI2 content increasing, the indirect optical band gaps are decreased from 0.662 to 0.622eV according to Tauc laws. The introduction of SnI2 makes the glasses much easier to prepare and more stable against crystallization, making them drawable as optical fibers. The highest ΔT (130°C) value for (Ge20Se15Te65)0.9–(SnI2)0.1 glass composition can be obtained. A slight red-shifting of the long-wavelength cutting-off edge from 18.4 to 19.4μm was shown and it seems that SnI2 in these glasses offers the improvement in the far-infrared properties. [Copyright &y& Elsevier]

Silver nanoparticles (NPs) were introduced into the Er3+-doped tellurite glasses (TeO2–Bi2O3–TiO2) and their effects on the 1.53µm band fluorescence of Er3+ and thermal stability of glass host were investigated. It was found that the presence of silver NPs nucleated and grown during the heat annealing process, could improve the thermal stability and the 1.53µm band fluorescence. Maximum enhancement in the 1.53µm band fluorescence was obtained in sample heat-treated for 48h. However, further increase in the heat annealing time (~72h) reduces the fluorescence intensity. Enhancement in the 1.53µm band fluorescence is attributed to the increased local electric field induced by silver NPs whereas the quenching is ascribed to the energy transfer from Er3+ ions to silver NPs. [ABSTRACT FROM AUTHOR]