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Chalcogenide solid‐state electrolytes (SSEs) have been receiving growing attentions due to their high ionic conductivity and suitable mechanic properties, especially the Li2S–P2S5 systems incorporated with a second glass network formers (Si, Ge, Sn, and so on) besides P. Although the ionic conductivities are generally enhanced with the second glass network formers, the comprehensive effects of different glass formers on other properties, including electrochemical, cycling, and air stability, remain elusive. To acquire deeper understanding, herein, three common but representative glass network formers (SiS2, GeS2, and SnS2) were introduced into Li2S–P2S5, and their individual effects were investigated systematically. The results of multiscale characterizations before and after lithium stripping/plating cycling confirmed that the introduction of metal cations (Ge, Sn) generally leads to worse electrochemical stability and shorter cycle life of these SSEs toward lithium metal compared with SSEs with nonmetal cation (Si) modification. However, the air stability is related to the binding energy of M–S (M = Si, Ge, Sn), which is consistent with the hard base soft acid theory. This work provides valuable understanding for designing pragmatic Li2S–P2S5–MS2‐based SSEs with high electrochemistry, cycling, and air stability. [ABSTRACT FROM AUTHOR]

Novel chalcogenide glasses of pseudo-binary (100 – x)Sb2S3–xCuI systems were synthesized by traditional melt-quenching method. The glass-forming region of Sb2S3-CuI system was determined ranging from x = 30 mol% to 40 mol%. CuI acts as a non-bridging modifier to form appropriate amount of [SbSI] structural units for improving the glass-forming ability of Sb2S3. Particularly, as-prepared glassy sample is able to transmit light beyond 14 μm, which is the wider transparency region than most sulfide glasses. Their physical properties, including Vickers hardness (Hv), density (ρ), and ionic conductivity (σ) were characterized and analyzed with the compositional-dependent Raman spectra. These experimental results would provide useful knowledge for the development of novel multi-spectral optical materials and glassy electrolytes. [ABSTRACT FROM AUTHOR]

The glass‐ceramics of AgI‐based electroconductive chalcogenide system was realized using an appropriate heat treatment at a fairly high temperature (Tg + 40°C) and different times ranging from 4 to 20 hours. The crystallization behavior and electroconductive properties of the heat‐treated samples were studied in detail. Transmission study was performed, and the results show that the cut‐off edge of the short wavelength is red‐shifted at prolonged annealing time but remains an excellent transmittance in the mid‐infrared (IR) region. XRD and scanning electron microscopy results indicated that the precipitated crystalline phases are mainly β‐/γ‐AgI. Moreover, a small amount of α‐AgI, which rarely existed at room temperature, is precipitated in the AgI‐rich chalcogenide glass‐ceramics. The ionic conductivity of all glass‐ceramics was enhanced by heat treatment in contrast to that of base glass. Raman analysis exhibited the structure variation in the glass sample after heat treatments. This study provided an observation of crystallization in chalcogenide glass containing large amounts of AgI and be of good guidance to fabricate novel AgI‐based chalcogenide glass‐ceramics that can be candidates in infrared optics and solid electrolyte applications. [ABSTRACT FROM AUTHOR]

A novel family of Ga2S3-Sb2S3-XI (XI = PbI2, CsI, AgI) was investigated to understand the role of metal halides and exploit new chalco-halide glasses for infrared optics. The dependence of the thermal properties, infrared optical properties, and structural information of the novel family on different metal-iodines was investigated. Results showed that metal halides increase the glass stability but decrease the glass network connectivity. The compositional dependence of the short-wave cut-off edge is associated with the electronegativity difference between the cations and anions of the metal halides. Raman study showed that the metal- iodine modified the glass structure mainly through the iodide content, and the cations dissolved in the glass network mostly as charge compensators for the aperiodic network. For the glasses in the series Ga2S3-Sb2S3-XI-Dy3+, Dy3+ emission increased in the PbI2- and CsI-doped glasses but decreased in the AgI-doped glass due to the combined effect of dysprosium and oxygen. For all that, these novel glasses are highly promised for use in infrared optics. [ABSTRACT FROM AUTHOR]

Series of glassy and glass-ceramic samples in the GeSe2-Ga2Se3-NaI system is prepared by melt-quenching technique and the glass-forming region is well-defined by XRD investigations. Na-ion conduction behavior is systemically studied by impedance measurements. For the glasses in the series (100 - 2x)GeSe2-xGa2Se3-xNaI, ionic conductivities increased with increasing x, whereas the attributed activation energy of ion conduction decreases. The enhanced mechanism is discussed by employing Raman spectra. In addition, the effect of the crystal phases NaI and Ga2Se3 on the ionic conduction behavior in the (70 - x)GeSe2-xGa2Se3-30NaI samples is discussed. Although it shows that the poorly conducting crystallites of NaI and Ga2Se3 have a negative effect on the ionic conductivities in this series, the highest ionic conductivity of 1.65 × 10-6 S/cm is obtained in the 45GeSe2-25Ga2Se3-30NaI glass. Finally, this study also demonstrates a possible way to search appropriate Na-ion solid electrolytes for allsolid-state batteries. [ABSTRACT FROM AUTHOR]

Diagram of the phase transformation behavior of GeS2- Ga2 S3- CsI glasses is realized in this article and the structure-property dependence of the chalcogenide glasses is elucidated using differential scanning calorimetry and Raman spectroscopy. We observe the compositional threshold of crystallization behavior locates at x = 6-7 mol% in (100− x)(0.8 GeS2-0.2 Ga2 S3)- x CsI glasses, which is confirmed by the thermodynamic studies. Structural motifs are derived from the Raman result that [ Ge( Ga) S4], [ S2 GeI2], [ S3 GaI], and [ S3 Ga- GaS3] were identified to exist in this glass network. Combined with the information of structural threshold, local arrangement of these structural motifs is proposed to explain all the experimental observations, which provides a new way to understand the correlation between crystallization behavior and network structure in chalcogenide glasses. [ABSTRACT FROM AUTHOR]

We report the fabrication and characterization of 80GeS2·20Ga2S3:0.5Tm2S3 chalcogenide glass-ceramics. A careful thermal process has led to the formation of ∼50 nm Ga2S3 nanocrystals. By monitoring the 3H5→3F4 Tm3+ transition, an almost fivefold increase of in the intensity and ∼76 μs prolongation in the lifetime of mid-infrared fluorescence at 3.8 μm have been observed after crystallization. Element mapping evidenced that enhancement in the mid-infrared emission intensity was related to the formation of Ge-rich region in the glass-ceramics, consistent with spectroscopic results from glasses with different levels of GeS2 content and β-GeS2 precipitation. [ABSTRACT FROM AUTHOR]

Abstract: Novel chalcogenide glasses based on GeS2–In2S3–Sb2S3 system were prepared by conventional melt-quenching method and their physicochemical properties, e.g. glass transition temperature, density, and Vickers micro-hardness, were studied in detail. The results show that the thermal, mechanical, and optical properties depend largely on four-coordinated Ge or In entities and are sensitive to the variation of the connectivity in the GeS2–In2S3–Sb2S3 glass network. It is a promising chalcogenide glass system suitable for rare earth doping or crystallization of rare earth doped crystals, which aims at optical applications of IR optical amplifier or efficient solid state laser. [Copyright &y& Elsevier]

Transparent 90GeS⋅10GaS(G10) chalcogenide glass-ceramics containing β-GeS nanocrystals was successfully fabricated through controllable crystallization based on the knowledge of its nucleation-rate-like curve. Using the conventional Z-scan method, both large spectral dependence and crystallinity dependence of optical nonlinear parameters were learned under the excitation of different wavelengths that in proximity of the half-bandgap. In particular, a large value of figure of merit (FOM≈11.64) was obtained in the crystallized sample after the heat-treatment at 466°C for 40 h. Although it is not a straightforward process to select an appropriate medium for a specific application, this work opens a new way to construct suitable optical nonlinear properties (e.g., large FOM) though modifying the microstructure of chalcogenide glass-ceramics. [ABSTRACT FROM AUTHOR]

Abstract: The information of phase transformation is attained by in situ XRD experiments leading to the knowledge of topological threshold in GeS2–Ga2S3 glasses. The turning point of phase transformation behavior is demonstrated to be glasses containing 14–15mol% Ga2S3. To interpret it a network demixing model is further improved and proposed for the structure of these ternary or quasi-binary chalcogenide glasses. For the nearest-neighbor coordination environment of glass with a transitional composition of 85.7mol% (6/7) GeS2·14.3mol% (1/7) Ga2S3, six-coordinated [S3Ga–X–GaS3] units (X=S or None) are well isolated by the [GeS4] structures, which contributes to the decreasing of precipitation of Ga2S3 crystals in (100−x)GeS2–xGa2S3 (x≤14.3) glasses corresponding to the experimental evidence of the phase transformation behavior. This scenario of intermediate-range structural order, firstly, includes the arrangement of structural units which is consistent with and provides an atomistic explanation of the compositional evolution of phase transformation behavior in these glasses. [Copyright &y& Elsevier]

Abstract: IR transparent bulk-crystallized chalcogenide glasses purely containing nontoxic and excellent nonlinear optical crystallites AgGaGeS4 were fabricated through careful ceramization process of the as-prepared glasses with the composition 53GeS2·47AgGaGeS4 at a temperature of 350°C for various durations. The second-order optical nonlinearity of bulk-crystallized chalcogenide glasses was discussed on the basis of Maker fringe theory. A large second-order optical nonlinearity (for λ =1064nm) up to 5.79pm/V, was evaluated in the IR transparent chalcogenide glass bulk-crystallized for 24h. [Copyright &y& Elsevier]

Abstract: Defect configurations of Ge–S binary glasses have been studied systemically by Raman scattering technique and positron annihilation lifetime spectra (PALS). The correlations between the positron lifetime data, structural features, and chemical compositions of Ge–S binary glasses have been established, and also the identification of open volume originated from coordination defects has been carried out. The cognizance of defect configuration will be very helpful to further understand the unique photosensitivity of chalcogenide glasses. [Copyright &y& Elsevier]

The infrared (IR) transmitting nanocrystallized chalcogenide glass only containing α-CdGa2S4 IR nonlinear optical crystallites, which were confirmed by x-ray diffraction and Raman scattering measurements, was fabricated through the controllable nucleation and crystallization of the glass with the composition 82GeS2·18CdGa2S4 at a temperature of 325 °C far below the glass transition temperature (Tg:415 °C) for a long duration. A clear second harmonic generation (green light, 532 nm) could be observed in the transparent 82GeS2·18CdGa2S4 nanocrystallized chalcogenide glass, demonstrating the IR frequency-doubling function of the prepared nanocrystallized composite material. [ABSTRACT FROM AUTHOR]

In this study, convex microlens arrays (MLAs) on chalcogenide glass (ChG) surface were fabricated through femtosecond laser direct writing and precision molding. Femtosecond laser writing was first employed to induce regularly arranged damage craters on the surface of silica glass. Then, the surface of silica was etched with hydrofluoric acid to obtain a smooth concave MLA. Finally, the concave microlens of silica was replicated on the surface of ChG by precision molding to obtain ChG MLA. The resulting ChG MLA had a uniform structure, clear image, and good focusing effect. By optimising the parameters of laser direct writing and chemical etching, we produced 1600 rectangular and hexagonal microlenses from As 2 Se 3.The optical performances of MLAs were demonstrated by their excellent imaging and focusing capabilities. The method applied provides an efficient way to prepare large-scale MLA masks and MLAs. [ABSTRACT FROM AUTHOR]

• Studies on the acousto-optical properties of near-infrared chalcogenide glasses-ceramics were developed. • A new photoelesticity measurement system operating at 1550 nm was developed and used to characterise the photoelasticity coefficient and M 2. • The precipitation of halide crystal CsCl in chalcogenide glass can achieve the reduction of acoustic attenuation, and the negative effect on M 2 was small. Crystallization of chalcogenide glasses provides a new possibility to decoupling the trade-off between acousto-optic figure of merit (M 2) and acoustic attenuation (α) properties of acousto-optic materials. In this work, 62.5GeS 2 -12.5Sb 2 S 3 -25CsCl chalcogenide glasses ceramics were prepared, and CsCl nanocrystals were precipitated and evidenced by using scanning electron microscopy and X-ray diffractometer. The precipitation of CsCl nanocrystals led to a 10 % decrease in M 2 from 113.85 to 102.08 × 10−18 s3/g, but also to a substantial improvement in α , which decreased by 38 % from 3.28 to 2.03 dB/cm. The glass crystallization that together with a rearrangement of the glass network structure would result in the enhancement of network rigidity of the residual glass matrix, thus contributing to the reduction of acoustic attenuation. [ABSTRACT FROM AUTHOR]

• Photostability of Ge-S films under fs-laser was studied; • S-rich and S-deficient films exhibit opposite reaction to fs-laser irradiation; • GeS 1.5 film possesses the highest fs-laser stability; • Distortion of [GeS 6 ] octahedra is the origin of fs-laser instability of Ge-S films. The composition dependent photostability of chalcogenide thinfilms (ChTFs) within a germanium-sulfur (Ge-S, GS) binary system was investigated via subjecting a series of GS ChTGs with different Ge/S ratios to femtosecond laser irradiation at a power density in order of megawatt per square centimeter. The experimental results show that the amount of [GeS 6 ] octahedra existing in the ChTGs is the key factor that influences their photostability. A GeS 1.5 film which contains equal amount of [GeS 6 ] octahedra and [GeS 4 ] tetrahedra in its glass network has been discovered to possess the highest fs-laser stability, and such fs-laser resistant ChTF could be a promising substrate for manufacturing micro-nano nonlinear photonic devices that function at high pumping power. [ABSTRACT FROM AUTHOR]

Ge-rich glass-ceramics sandwiched by GeS crystalline layers were fabricated through 10 h thermal treatments at different temperatures. Surface crystallization is evidenced by XRD investigation of glass-ceramic samples polished by different times. SEM observation shows that the thickness of the crystalline layer is about 100 µm for the sample thermally treated at 395 °C for 10 h. The physical properties, including transmission spectra, density, Vickers hardness, and thermal expansion coefficient, were characterized and discussed with the evolution of GeS crystalline layers. This work not only establishes the correlation between microstructure and physical properties of chalcogenide glass-ceramics sandwiched by GeS, but also provides important evidence of structural similarity for understanding the network structure of Ge-S chalcogenide glasses. [ABSTRACT FROM AUTHOR]

Glassy and partially crystallized samples of (Ge 1−x Ga x )S 2 (0 mol% ≤ x ≤ 50 mol%) were prepared and investigated for the Ga effect on their physical and structural properties. For low Ga content (0 mol% ≤ x ≤ 30 mol%), homogeneous glassy samples were prepared and present good physical properties, such as high glass transition temperature (>400 °C) and Vickers hardness (>2.60 GPa). With the Ga substitution for Ge, the thermal stability of samples decreases, leading to the precipitation of α-Ga 2 S 3 crystallites when x > 40 mol%. Structural evolution of (Ge 1−x Ga x )S 2 samples was investigated by Raman spectra and X-ray diffraction techniques. The correlation between the physical properties and structural evolution was established. [ABSTRACT FROM AUTHOR]

Mid-infrared (MIR) laser operating at 2–5 μm has gained increasing interest because of the extensive applications in fields from biomedicine, sensing to nanomaterial science. Chalcogenide glass (ChG) is a kind of matrix that is promising for MIR laser due to its low phonon energy and wide infrared transmittance region. However, significant challenges in the enhancement of MIR optical properties of rare-earth ion-doped ChGs still exist. Here, enhanced MIR emission was realized in Pr3+-doped chalcogenide glass ceramics (ChGCs). By controlling the heat treatment temperature and duration, biphasic-phase nanocrystals of Ga 2 Se 3 and GeSe 2 were successively precipitated in the glass host. Compared to the as-prepared glass, the GCs exhibit an obvious increase in emission intensity by more than 5 times. The improvement of the MIR emission may be induced by the enhanced cross-relaxation between Pr3+ ions and the increased multiple scattering effects. Furthermore, the obtained ChGC enables large stimulated emission cross section 0.42 × 10−20 cm2 at 2.44 μm and 0.62 × 10−20 cm2 at 4.75 μm. The superior optical properties of the ChGC indicate that it is an attractive candidate for MIR laser. • Biphasic-phase nanocrystals of Ga 2 Se 3 and GeSe 2 embedded glass-ceramic was prepared by controlled heat treatment. • Enhanced MIR emission of Pr3+ was observed in the glass ceramics. • Effect of biphasic-phase nanocrystals on the enhancement of MIR emission was investigated. • The glass-ceramic with large stimulated emission cross section endows its potential application in MIR laser. [ABSTRACT FROM AUTHOR]

Germanium (Ge)-sulfur (S) (GeS) binary system is a simple and green chalcogenide glass system. In this work, we prepared a Ge-rich non-stoichiometric GeS film and investigated its optical property and network structure. Findings show that improving or modifying the optical properties (optical transmittance, refractive index, etc.) of the GeS film with a one-step annealing process, and the structural evolution of GeS film network that is attribute to the annealing-induced property changing is identified. [ABSTRACT FROM AUTHOR]

Abstract: Chalcogenide glasses in the GeS2–Ga2S3–Ag2S pseudo-ternary system were prepared by melt-quenching technique. The structural evolvement of the glasses was studied by Raman spectroscopy. The Raman results show that the addition of Ag2S involves the breaking of [S3Ge–GeS3] ethane-like units and the formation of Ag–S ionic bonds. The results of differential scanning calorimetry (DSC) show that the glasses have relatively high-glass transition temperatures and good thermal stabilities. These GeS2–Ga2S3–Ag2S glasses have a wide range of transmission approximately from 0.50 to 12.5μm. In addition, with the method of Maker fringe, SHG was observed in the 0.9GeS2–0.05Ga2S3–0.05Ag2S glass irradiated by an electron beam. The value of second-order nonlinear optical susceptibility d is as large as 6.6pm/V, and the poling mechanism of electron beam irradiation was also discussed in this work. [Copyright &y& Elsevier]

Abstract: The results of the femtosecond time-resolved optical Kerr at 820nm in GeS2–In2S3 chalcogenide glasses indicate that the response time in GeS2–In2S3 glasses is subpicosecond, which is predominantly due to the distortion of the electron cloud. The value of χ (3) in 0.95GeS2–0.05In2S3 glass is also as large as 2.7×10−13 esu, and it reduces with the addition of In2S3, which may be ascribed to the microstructure evolution of GeS2–In2S3 glasses. It is deduced that the intrinsic [Ge(In)S4] tetrahedral structure units that possess the high hyperpolarizability may do great contribution to the enhancement of third-order optical nonlinearity while [S3Ge–GeS3] ethane-like molecular units make no considerable contribution to that in femtosecond time scale. These GeS2–In2S3 and GeS2–In2S3-based chalcogenide glasses would be expected to be the promising materials for all-optical switching devices. [Copyright &y& Elsevier]

Abstract: GeS2 based multi-component chalcogenide glasses, Ge–S–Sb(Cd), were prepared in series. With femtosecond time-resolved optical Kerr gate technique, we investigate their ultrafast third-order nonlinear optical (NLO) properties. The strongest NLO response comes from 0.70GeS2–0.30Sb2S3. Its χ(3), 1.8×10−12 esu, is more than three times to GeS2 glass. Their instant NLO responses are within 120fs pulse duration. We suggest that lone-pair electrons from highly polarizable Sb atom in [SbS3] structure unit play an important role for the enhanced NLO response. This enhancement is much stronger to the contribution from S–S covalent bond. [Copyright &y& Elsevier]