Sb Se Research Articles

Re-optimization of the binary Sb − Se system aided by ab-initio calculations

Based on the ab-initio calculations the thermodynamics of the Sb2Se3 intermediate phase was modeled and used in the calculations of the Sb–Se phase diagram together with the thermodynamic properties of liquid phase elaborated by the association model. The modeled heat capacity of Sb2Se3 phase shows excellent agreement with the experiment data available in the literature in the wide temperature range. The calculated equilibrium lines of the Sb–Se phase diagram good correlate with the experimental ones. The determined thermodynamic parameters can be applied in future calculations of the high-ordered systems and for determination of the Sb2Se3 thermoelectric properties.

Thermodynamic Study of the Ag–Sb–Se System by the EMF Method with Ag4RbI5 Solid Electrolyte

Thermodynamic Study of the Ag–Sb–Se System by the EMF Method with Ag4RbI5 Solid Electrolyte

Polycomponent doping improved thermoelectric performance of Cu<sub>3</sub>SbSe<sub>4</sub>-based solid solutions

<sec> Cu<sub>3</sub>SbSe<sub>4</sub>, one of the ternary p-type semiconductor materials with chalcopyrite structure, has aroused much interest in thermoelectrics due to its inherent large effective mass and narrow bandgap. Therefore, many researches have been done, which cover the single and/or multi-element doping to manipulate its band structure and introduce the point defects. Although great achievements have been made in recent years, the mechanism in Cu<sub>3</sub>SbSe<sub>4</sub> with respect to the phonon and electronic transport properties needs further investigating. </sec><sec> In this work, first, Sn and S are co-doped into Cu<sub>3</sub>SbSe<sub>4</sub> and then the resulting compound is alloyed with Ga<sub>2</sub>Te<sub>3</sub>, to improve its TE performance and understand the mechanism by calculating the band structure and crystal structure. The calculation of band structure reveals that an impurity band is created within the bandgap after co-doping Sn and S due to their contributions to the density of the states (DOS), which is directly responsible for the significant improvement in carrier concentration (<i>n</i><sub>H</sub>) and electrical property. Therefore, the power factor (PF) is enhanced from 0.52 × 10<sup>–3</sup> to 1.3 × 10<sup>–3</sup> W·m<sup>–1</sup>·K<sup>–2</sup>. </sec><sec> Although the effect associated with the Ga (Te) residing at Sb (Se) sites on the band structure is limited due to the fact that both the single Ga- and single Te-doped band structure remain almost unchanged, the structural parameters (bond lengths and angles) of the polyhedrons [SeCu<sub>3</sub>Sb] and [SbSe<sub>4</sub>] before and after Te and Ga residing at Se and Sb sites respectively change remarkably. This yields the significant distortion of local lattice structure on an atomic scale. Therefore, the phonon scattering is enhanced and the lattice thermal conductivity (<i>κ</i><sub>L</sub>) decreases from 1.23 to 0.81 W·K<sup>–1</sup>·m<sup>–1</sup> at 691 K. The reduction in <i>κ</i><sub>L</sub> prevents the total thermal conductivity (<i>κ</i>) from being enhanced rapidly. As a consequence, the highest ZT value of 0.64 is attained, which is much higher than that of the pristine Cu<sub>3</sub>SbSe<sub>4</sub> (ZT = 0.26). In addition, we not only present a synergistic strategy to separately optimize the phonon and electronic properties, but also fully elaborate its mechanism and better understand that this strategy is an effective way to improve the TE performance of the Cu<sub>3</sub>SbSe<sub>4</sub>-based solid solutions.</sec>

Compositions, structures, and mid-infrared transparency of Sb–Te–Se thin films synthesized using a combinatorial method

The dielectric function of phase-change materials (PCMs) presents a tremendous difference for the amorphous and crystalline states. Therefore, the measurement of the mid-infrared transparency of thin films of PCMs will provide a cost-efficient method to reveal the dependence of amorphous-crystalline phase transition on their compositions. Although Sb–Te–Se system has shown the advantages of the high speed, low power consumption and long retention life, the information on the mid-infrared transparency of Sb–Te–Se thin films is still insufficient. In our investigation, combinatorial materials libraries of Sb–Te–Se thin films were synthesized. The composition and mid-infrared spectral transmittance of each pixel of Sb–Te–Se thin film in the library were characterized using the energy dispersive X-ray analysis (EDX) and Fourier-transform infrared (FTIR) spectrometer, respectively. The in-depth chemical composition for randomly selected pixels was identified using secondary ions mass spectroscopy (SIMS). The crystallographic structure of some pixels was also identified using micro-area X-ray diffraction (μ-XRD). It can be found that, with the change of composition in Sb–Te–Se thin films, their mid-infrared spectral transmittance can be organized into three distinctive groups, corresponding to amorphous Sb–Se, Sb2Se3 orthorhombic structure and Sb2Te3 rhombohedral structure, respectively. Therefore, the amorphous-crystalline phase transition and the phase-change from the orthorhombic structure of Sb2Se3 to the rhombohedral structure of Sb2Te3 can be completely reflected in the mid-infrared spectral transmittance of Sb–Te–Se thin films.

Evaluating the cytotoxicity of Ge-Sb-Se chalcogenide glass optical fibres on 3T3 mouse fibroblasts.

In vivo cancer detection based on the mid-infrared molecular fingerprint of tissue is promising for the fast diagnosis and treatment of suspected cancer patients. Few materials are mid-infrared transmissive, even fewer, which can be converted into functional, low-loss optical fibres for in vivo non-invasive testing. Chalcogenide-based glass optical fibres are, however, one of the few. These glasses are transmissive in the mid-infrared and are currently under development for use in molecular sensing devices. The cytotoxicity of these materials is however unknown. The cytotoxicity of Ge–Sb–Se chalcogenide optical glass fibres on 3T3 mouse fibroblast cells is here investigated. Fibres exposed to four different pre-treatment conditions are used: as-drawn (AD), propylamine-etched (PE), oxidised-and-washed (OW) and oxidised (Ox). To achieve the latter two conditions, fibres are treated with H2O2(aqueous (aq.)) and dried to produce a surface oxide layer; this is either washed off (OW) or left on the glass surface (Ox). Cellular response is investigated via 3 day elution and 14 day direct contact trials. The concentration of the metalloids (Ge, Sb and Se) in each leachate was measured via inductively coupled plasma mass spectrometry. Cell viability is assessed using the neutral red assay and scanning electron microscopy. The concentration of Ge, Sb and Se ions after a 3 day dissolution was as follows. In AD leachates, Ge: 0.40 mg L−1, Sb: 0.17 mg L−1, and Se: 0.06 mg L−1. In PE leachates, Ge: 0.22 mg L−1, Sb: 0.15 mg L−1, and Se: 0.02 mg L−1. In Ox leachates, Ge: 823.8 mg L−1, Sb: 2586.6 mg L−1, and Se: 3750 mg L−1. Direct contact trials show confluent cell layers on AD, PE and OW fibres after 14 days, while no cells are observed on the Ox surfaces. A >50% cell viability is observed in AD, PE and OW eluates after 3 days, when compared with Ox eluates (<10% cell viability). Toxicity in Ox is attributed to the notable pH change, from neutral pH 7.49 to acidic pH 2.44, that takes place on dissolution of the surface oxide layer in the growth media. We conclude, as-prepared Ge–Sb–Se glasses are cytocompatible and toxicity arises when an oxide layer is forced to develop on the glass surface.

TRIANGULATION OFTHE Cu-Sb-Se SYSTEM

Thermoelectric technologies allow the direct conversion of waste heat into electricity. A new strategy for finding promising thermoelectric materials is to study the phase diagrams of multicomponent systems. Analysis of recent investigations indicates high perceptivity of Cu2Se phase, due to abnormally low values of the thermal conductivity and high values of electrical conductivity. Other thermoelectric materials based on copper have attractive properties, such as: diamond-like compounds, argyrodites, oxiselenides, tetrahedron-type compounds and others. Due to this a more detailed investiation of the Cu–Sb–Se system are actually. An important step in the study of the system is the determination of quasi-binary sections by carrying out the triangulation. For this purpose, the quasi-binarity of sections in the ternary Cu–Sb–Se system at a temperature of 523 K was determined by X-ray diffraction analysis. Since the annealing temperature in the synthesis process is 523 K, six binary Cu2Se, CuSe, CuSe2, Cu1.6Sb0.4, Cu2Sb, Sb2Se3 and three ternary compounds CuSbSe2, Cu3SbSe3, Cu3SbSe4 took part in the triangulation of the system. Analysis of the early studies showed the presence of three quasi-binary sections in the Cu–Sb–Se system: Cu2Se – Cu3SbSe3, Cu3SbSe3 – CuSbSe2 and CuSbSe2 – Sb2Se3, and the character of the remaining 12 sections requires experimental studies. The quasi-binary section of Cu2Se-Sb2Se3 divides the general system of Cu-Sb-Se into two subsystems: Cu2Se-Sb2Se3-Se (30 intersection points) and Cu-Sb-Sb2Se3-Cu2Se (13 intersection points). To optimize the process of triangulation, it was decided to carry out it in stages: synthesis and study of the point in the most informative phase field with following separation and exclusion of quasi-binary and non-quasi-binary sections. Such approach makes it possible to reduce the number of syntheses and the number of used substances. Phase analysis was performed by comparing experimental and calculated from the literature powder patterns of phases present in the systems Cu2Se-Sb2Se3-Se and Cu-Sb-Sb2Se3-Cu2Se. The obtained results indicate that in the subsystem Cu2Se-Sb2Se3-Se has seven stable sections, all of which are based on the ternary compound Cu3SbSe4. In the Cu-Sb-Sb2Se3-Cu2Se subsystem, 5 quasi-binary sections are stable: three based on binary Cu2Se and two sections based on ternary compounds CuSbSe2 and Cu3SbSe3.

Optical and structural modification in amorphous Ge24Se61Sb15 thin films under 80 MeV Silicon swift heavy ions for telecom and optical applications

Present study reports about the effect of 80 MeV Silicon swift heavy ions irradiation on linear and nonlinear optical properties of amorphous Ge24Se61Sb15 thin films. Optical changes are correlated with structural modifications for their utilization in telecom and optical applications. Optical transmission spectra were recorded from 200 nm to 1100 nm. Linear refractive index is calculated by optical transmission using Swanepoel envelope method. Dispersion in the linear refractive index of the thin films is described using Wemple-DiDomenico model. Nonlinear optical parameters are determined using semi-empirical relations. Optical band gap is calculated by extrapolating the Tauc's plot. The investigation shows that optical band gap decreases from 1.64 eV to 1.47 eV and linear refractive index increases from 2.50 to 2.59 till fluence 1 × 1012 ions/cm2. In addition, third-order nonlinear susceptibility increases from 8.178 × 10−10 [esu] to 11.43 × 10−10 [esu] and nonlinear refractive index increases from 1.742 × 10−10 [esu] to 2.698 × 10−10 [esu] till fluence 1 × 1012 ions/cm2. Raman measurements reveal that swift heavy ion irradiation converts homopolar Ge–Ge, Sb–Sb bonds into hetropolar Ge–Sb and Se–Sb bonds, which is responsible for observed optical changes. The changes are understood in terms of glass network structure and electronic energy loss for application point of view.

Impurity Phases and Optoelectronic Properties of CuSbSe2 Thin Films Prepared by Cosputtering Process for Absorber Layer in Solar Cells

When there is a choice of materials for an application, particular emphasis should be given to the development of those that are low-cost, nontoxic, and Earth-abundant. Chalcostibite CuSbSe2 has gained attention as a potential absorber material for thin-film solar cells, since it exhibits a high absorption coefficient. In this study, CuSbSe2 thin films were deposited by radio frequency magnetron cosputtering with CuSe2 and Sb targets. A series of CuSbxSe2 thin films were prepared with different Sb contents adjusted by sputtering power, followed by rapid thermal annealing. Impurity phases and surface morphology of Cu–Sb–Se systems were directly affected by the Sb sputtering power, with the formation of volatile components. The crystallinity of the CuSbSe2 thin films was also enhanced in the near-stoichiometric system at an Sb sputtering power of 15 W, and considerable degradation in crystallinity occurred with a slight increase over 19 W. Resistivity, carrier mobility, and carrier concentration of the near-stoichiometric thin film were 14.4 Ω-cm, 3.27 cm2/V∙s, and 1.33 × 1017 cm−3, respectively. The optical band gap and absorption coefficient under the same conditions were 1.7 eV and 1.75 × 105 cm−1, which are acceptable for highly efficient thin-film solar cells.

Theoretical investigation of the electronic structure and anisotropic optical properties of quasi-1D Sb2Se3 photovoltaic absorber materials

Sb2Se3 is a nontoxic, environmentally friendly photovoltaic absorber material with both a narrow bandgap and high absorption coefficient. The optical properties of Sb2Se3 crystals are theoretically studied herein using first-principles methods. The crystal structure, electronic structure, dielectric function, and absorption coefficient are calculated. The results show that the quasi-one-dimensional structure of Sb2Se3 has an indirect bandgap with a value of 0.953 eV. The bottom of the conduction band and the top of the valence band are mainly formed by Sb 5p and Se 4p hybridized orbitals. For light incident along the [100], [010], and [001] directions, the real and imaginary parts of the dielectric function exhibit clearly anisotropic characteristics. The absorption coefficient is greater than 105 cm−1.

Ultralow Thermal Conductivity in Cs–Sb–Se Compounds: Lattice Instability versus Lone-Pair Electrons

The presence of lone-pair electrons (LPE) is known to lead to large anharmonicities in materials and thus to low lattice thermal conductivity (κ). Materials with LPE typically have κ values that ar...

TlSbP2Se6 - a new layered single crystal: growth, structure and electronic properties

Successful synthesis by vertical solidification (Bridgman - Stockbarger) technique is reported for a centimetre size noncentrosymmetric TlSbP2Se6 crystal (for the first time) with excellent transparency at 0.75–10 μm that is very useful for its practical application. The high homogeneity and stoichiometric composition have been confirmed by SEM-EDX. Next we determined the crystal structure, electronic properties by use of both experimental and theoretical methods. The layered structure of the crystal provides strong anisotropy of physical properties. Special attention was placed for an explanation of the source of the layer architecture and its effect on the strong anisotropy of properties. In particular, employing the XPS method, we have measured for the TlSbP2Se6 crystal the binding energies of core-level electrons as well as energy distribution of the valence electrons for both pristine and treated with Ar+ ions surfaces and shown that the TlSbP2Se6 crystal surface is highly hygroscopic. For interpretation and explanation of the measured XPS valence band spectrum, we examined different approaches for exchange correlation (XC) potential with a density functional theory (DFT) framework and found that the best agreement of the shapes of the XPS spectrum and the curve of total density of states is derived when the band structure calculations were made employing for XC potential modified Becke-Johnson (mBJ) functional in the form of Tran and Blaha. Based on the results of XPS measurements and calculations, we explained the contributions of individual ions to the band structure and convincingly demonstrated that ionic components of the chemical Sb–Se (P–Se) bonds in the TlSbP2Se6 crystal are similar to those of its silver-bearing counterpart AgSbP2Se6. The present DFT calculations within TB-mBJ + U + SO approach reveal that the TlSbP2Se6 compound is a non-direct semiconductor with Eg = 1.765 eV confirmed by UV-VIS measurements (1.75 eV). The main optical constants are explored in detail for TlSbP2Se6, as based on TB-mBJ + U + SO calculations. Finally, the result of the XPS investigations of the crystal surface after treatment with Ar+ ions supported by the calculations of the structure indicates its high chemical and mechanical resistance, which, despite the dangerous element contained in the composition, indicates its safe use in optoelectronic devices.

Lattice Dynamics of Sb2Se3 from Inelastic Neutron and X‐Ray Scattering

The lattice dynamics of orthorhombic Sb2Se3 is studied by a combination of inelastic neutron and 121Sb nuclear inelastic scattering giving access to the total and Sb partial density of phonon states (DPS). The Se partial DPS is determined from the difference between the total and Sb partial DPS. The total DPS is determined at 39, 150, and 300 K, and an analysis of the temperature‐induced mode shifts in combination with low‐temperature powder diffraction data is provided. Using an earlier reported theoretical approach, the corresponding total and partial DPS of Sb2Se3 are calculated by first‐principles calculations. Herein, a detailed analysis of the Grüneisen parameter, element‐specific and bulk Debye temperatures, and the mean force constants as derived from the experimental data and discrete Fourier transform calculations is provided. In general, the calculations underestimate the strength of the covalent SbSe bonds.

Academic Well-Being and Structural Characteristics of Peer Networks in School.

Peer networks at school and students’ position in these networks can influence their academic well-being. We study here individual students’ network position (isolation, popularity, social activity) and peer network structures at the school level (centralization, density, clustering, school connectedness) and their relations to students’ academic well-being (school burnout, SB; schoolwork engagement, SE). Classroom surveys for 14–16-year-olds (N = 11,015) were conducted in six European cities (SILNE survey). Students were asked to nominate up to five schoolmates with whom they preferred to do schoolwork. SB and SE correlated negatively (−0.32; p < 0.0001). Students had on average 3.4 incoming (popularity; range 0–5) and 3.4 outgoing (social activity; 0–5) social ties. Percentage of isolated students was 1.4. Students’ network position was associated weakly with academic well-being—popular students had less SB and higher SE, and socially active students had higher SE. School-level peer networks showed high clustering and school connectedness, but low density and low centralization. Clustering was associated with higher SB. Low centralization and high school connectedness protected from SB. Dense networks supported SE as did high average school connectedness. Correlations between these network indicators and academic well-being were, however, low. Our study showed that both students’ network position and network characteristics at the school level can influence adolescents’ academic well-being.

New insight into the structure-property relationships from chemical bonding analysis: Application to thermoelectric materials

Structure-property relationships are indisputably important to deeply understand the nature of materials. The main direction pursued to investigate these relations is based on the chemical bonding concept. The integral and local properties of chemical bonding determined from the topological analysis of electron density by combining the quantum theory of atoms in molecules (AIM) and DFT calculations can aid to build a bridge between the atomic structure and the intrinsic properties of materials. In this paper, the electronic and thermal transport properties of thermoelectric materials in the Cu–Sb–Se system have been analysed by coupling energy densities relationships and corresponding electron density Laplacian distribution for specific interactions. The asset of this method is to directly highlight the influence of lone pair electrons and atomic fluctuations on interatomic interactions as well as the coupling effect of weak bonds, which offers a new approach to design and search for materials with low thermal conductivity at low calculation cost.

Optical properties and thermal stability of amorphous Ge–Sb–Se films

Ge–Sb–Se chalcogenide films with mean coordination number (MCN) from 2.27 to 2.66 were deposited by magnetron sputtering method. Annealing time dependent physical properties, such as refractive index, optical band gap, and thickness were investigated. It was found that, the Ge15Sb9.6Se75.4 film with MCN is 2.4 exhibits the smallest change ratio after long time (35 h) heat annealing in refractive index (<1%), optical band gap (<1%), and thickness (<3%). Together with the analysis of topological model, the component of Ge15Sb9.6Se75.4 with MCN is 2.4 can be considered as the best thermal stable film in this Ge–Sb–Se system. The film with larger refractive index of ~2.7 is very helpful to the application like chalcogenide waveguide.

Ternary selenides A2Sb4Se8 (A = K, Rb and Cs) as an n-type thermoelectric material with high power factor and low lattice thermal conductivity: importance of the conformationally flexible Sb-Se-Se-Sb bridges.

We investigated the thermoelectric properties of the layered ternary selenides A2Sb4Se8 (A = K, Rb and Cs) and the lattice thermal conductivity of K2Sb4Se8 on the basis of DFT calculations, to find that these selenides are a high-performance n-type thermoelectric material. The Seebeck coefficients and power factors calculated for the electron carriers of A2Sb4Se8 (A = K, Rb and Cs) are greater than those of the well-known thermoelectric materials Bi2Te3 and PbTe. The lattice thermal conductivity κlatt of K2Sb4Se8 is comparable to that of PbTe, well-known for its low lattice thermal conductivity. In terms of both electronic and phonon structures, the structural parts of the A2Sb4Se8 (A = K, Rb and Cs) phases crucial for their thermoelectric properties are the conformationally-flexible Sb–Se–Se–Sb bridges that interlink between their structurally rigid units.

Optical properties and microstructure of two Ge-Sb-Se thin films

Multipoint Cauchy method (MCM) is presented to investigate the refractive index and dispersion for each of Ge&lt;sub&gt;20&lt;/sub&gt;Sb&lt;sub&gt;15&lt;/sub&gt;Se&lt;sub&gt;65&lt;/sub&gt; and Ge&lt;sub&gt;28&lt;/sub&gt;Sb&lt;sub&gt;12&lt;/sub&gt;Se&lt;sub&gt;60&lt;/sub&gt; chalcogenide thin films at any wavelength in the transmission spectrum based on the regional approach method and Cauchy fitting. We theoretically calculate and compare the refractive index and dispersion curves obtained by using six different models. The results show that the most accurate results are obtained by the MCM. Two Ge—Sb—Se films are prepared by magnetron sputtering experimentally, and transmission spectrum curves are measured by Fourier infrared spectrometer, the noise is removed by segmental filtering and then the refractive index, dispersion, absorption coefficient, and optical band gap of the two films ina range of 500–2500 nm are obtained by the MCM. The results show that the refractive index of Ge&lt;sub&gt;28&lt;/sub&gt;Sb&lt;sub&gt;12&lt;/sub&gt;Se&lt;sub&gt;60&lt;/sub&gt; film is larger than that of Ge&lt;sub&gt;20&lt;/sub&gt;Sb&lt;sub&gt;15&lt;/sub&gt;Se&lt;sub&gt;65&lt;/sub&gt; film, which is caused by the higher polarizability and density of the former. The refractive indexes of both films decrease with wavelength increasing, so the long waves travel faster than short waves in the two films. The optical band gap of Ge&lt;sub&gt;28&lt;/sub&gt;Sb&lt;sub&gt;12&lt;/sub&gt;Se&lt;sub&gt;60&lt;/sub&gt; film (1.675 eV) is smaller than that of Ge&lt;sub&gt;20&lt;/sub&gt;Sb&lt;sub&gt;15&lt;/sub&gt;Se&lt;sub&gt;65&lt;/sub&gt; film (1.729 eV), and the corresponding wavelengths of the two are 740.3 nm and 717.2 nm. Finally, the microstructures of the two films are characterized by Raman spectra, and the reasons why the two chalcogenide films have different optical properties are explained from the bonding properties between the atoms.

Amorphous Ga–Sb–Se thin films fabricated by co-sputtering

Ternary chalcogenides of a Ga–Sb–Se system are prospective materials for potential applications in the field of infrared optics. This Letter deals with the optical properties and photosensitivity of Ga–Sb–Se thin films deposited by co-sputtering, enabling us to fabricate amorphous thin films outside the glass-forming region. The optical bandgap range of 1.92–1.35 eV with corresponding refractive indices at 1.55 µm ranging from 2.47 to 3.33 can be reliably covered using G a 2 S e 3 and S b 2 S e 3 targets. Furthermore, the prolonged irradiation by the near-bandgap light under the pure argon atmosphere leads to the irreversible photo-bleaching effect in fabricated films. The magnitude of this effect decreases monotonically with an increasing antimony content.

Effect of Nitrogen on the Amorphous Structure and Subthreshold Electrical Conduction of GeSeSb‐Based Ovonic Threshold Switching Thin Films

Herein, the amorphous structure of Ge–Se–Sb–N chalcogenide thin films is investigated through Raman, infrared, and X‐ray absorption spectroscopies in the light of the electrical performances of such materials once integrated in ovonic threshold switching (OTS) selector devices. In particular, it is shown that the presence of homopolar and wrong bonds in the amorphous structure has a detrimental impact on the subthreshold leakage current of the OTS devices. Although the presence of Sb–Sb and Ge–Sb bonds tends to increase the leakage current in pristine devices, the presence of Se–Se bonds is correlated to a significant device‐to‐device dispersion of subthreshold characteristics after the device initialization. Finally, the incorporation of a proper N concentration in Ge–Se–Sb glass permits to suppress the homopolar bonds, leading to a very low leakage current and a low device‐to‐device dispersion.

Broadband transparent optical phase change materials for high-performance nonvolatile photonics

Optical phase change materials (O-PCMs), a unique group of materials featuring exceptional optical property contrast upon a solid-state phase transition, have found widespread adoption in photonic applications such as switches, routers and reconfigurable meta-optics. Current O-PCMs, such as Ge–Sb–Te (GST), exhibit large contrast of both refractive index (Δn) and optical loss (Δk), simultaneously. The coupling of both optical properties fundamentally limits the performance of many applications. Here we introduce a new class of O-PCMs based on Ge–Sb–Se–Te (GSST) which breaks this traditional coupling. The optimized alloy, Ge2Sb2Se4Te1, combines broadband transparency (1–18.5 μm), large optical contrast (Δn = 2.0), and significantly improved glass forming ability, enabling an entirely new range of infrared and thermal photonic devices. We further demonstrate nonvolatile integrated optical switches with record low loss and large contrast ratio and an electrically-addressed spatial light modulator pixel, thereby validating its promise as a material for scalable nonvolatile photonics.