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We incorporate Se into the 3D halide perovskite framework using the zwitterionic ligand: SeCYS (+NH3(CH2)2Se-), which occupies both the X- and A+ sites in the prototypical ABX3 perovskite. The new organoselenide-halide perovskites: (SeCYS)PbX2 (X = Cl, Br) expand upon the recently discovered organosulfide-halide perovskites. Single-crystal X-ray diffraction and pair distribution function analysis reveal the average structures of the organoselenide-halide perovskites, whereas the local lead coordination environments and their distributions were probed through solid-state 77Se and 207Pb NMR, complemented by theoretical simulations. Density functional theory calculations illustrate that the band structures of (SeCYS)PbX2 largely resemble those of their S analogs, with similar band dispersion patterns, yet with a considerable bandgap decrease. Optical absorbance measurements indeed show bandgaps of 2.07 and 1.86 eV for (SeCYS)PbX2 with X = Cl and Br, respectively. We further demonstrate routes to alloying the halides (Cl, Br) and chalcogenides (S, Se) continuously tuning the bandgap from 1.86 to 2.31 eV-straddling the ideal range for tandem solar cells or visible-light photocatalysis. The comprehensive description of the average and local structures, and how they can fine-tune the bandgap and potential trap states, respectively, establishes the foundation for understanding this new perovskite family, which combines solid-state and organo-main-group chemistry.

The optically gated transistor (OGT) has been previously demonstrated as a viable selector device for memristor devices, and may enable optical addressing within cross-point arrays. The OGT current–voltage response is similar to a MOSFET device, with light activating the gate instead of voltage. The OGT also provides a naturally built-in compliance current for a series resistive memory element, determined by the incident light intensity on the gate, thus keeping the integrated periphery circuitry size and complexity to a minimum for a memory array. The OGT gate comprises an amorphous Ge2Se3 material that can readily be doped with other elements to alter the transistor's electrical properties. In this work, we explore the operation of the OGT when the Ge2Se3 gate material is doped with the Group IVA elements C, Si, Sn, and Pb. The dopant atoms provide changes to the optical and electrical properties that allow key electrical properties such as the dark current, photocurrent, switching speed, and threshold voltage to be tuned. [ABSTRACT FROM AUTHOR]

Gallylene supported by a bis(oxazolinyl)(phenyl)methanide (Boxm) ligand was synthesized and structurally characterized. The reaction of this gallylene with triphenylphosphine sulfide/selenide yielded dimeric gallium sulfide and selenide. These compounds could be converted to monomeric terminal sulfide and selenide by coordination of an external Lewis base such as an N‐heterocyclic carbene (NHC or IMe4) and 4‐dimethylaminopyridiene (DMAP). These doubly‐base‐stabilized gallium sulfide/selenide reacted with phenyl isocyanate to give the corresponding cycloadducts by releasing the Lewis base, indicating the formation of a single‐base‐stabilized gallium sulfide/selenide intermediate. [ABSTRACT FROM AUTHOR]

The structural and electronic properties of (CdS, CdSe, and CdTe) compounds in rock-salt, zinc-blend, and wurtzite crystal structures were calculated using ab initio calculation. In addition to these properties, the thermodynamic properties were added advantage to clarify their comportment as temperature variation. Under the context of density functional theory DFT, the calculations were carried out using the full potential linearized augmented plane wave FP-LAPW approach. The generalized gradient approximations GGA-PBE established by Perdew-Burke-Ernzerhof and the local density approximation LDA and modified Bucke Jhonson have both been employed for the exchange-correlation energy and related potential MBJ. The results show that the zinc-blend phases were the stable crystal structure for all compounds. The lowest direct band gap is found in the B3 phase for CdX, close to the experimental value. The values of band energies of CdS, CdSe, and CdTe were estimated to be 2,463 eV, 1,76 eV, and 1,532 eV, respectively. In general, this work fits well with other experimental and theoretical results. The quasiharmonic Debye theory is used to determine the impact of temperature and pressure on thermodynamic properties. This includes the calculation of pressure and temperature dependence, as well as the analysis of how heat capacity, thermal expansion, and the Debye temperature are affected by these variables. [ABSTRACT FROM AUTHOR]

Chalcogenide perovskites are promising lead-free, stable absorber materials for solar cells. This work reports the synthesis of orthorhombic phase pure CaSnS3 thin films by facile low temperature sulfurization of solution-processed CaSnO3 oxide precursors. Structural characterization confirms complete anion exchange to produce crystalline CaSnS3 films with vertically aligned rod-like grains. Optical studies show strong visible light absorption with direct bandgap of 1.72 eV, ideal for photovoltaics. Electrical measurements indicate p-type conductivity with hole concentration of 1.2×1017 cm-3 and mobility around 8 cm2V-1s-1 at room temperature. First-principles DFT calculations corroborate the p-type electronic structure. Prototype CaSnS3 solar cells are fabricated with TiO2 electrode, demonstrating power conversion efficiency of 2.5% under AM1.5G, open-circuit voltage of 0.55 V, short circuit current density of 11.5 mA/cm² and fill factor of 0.62. The cells also exhibit remarkable ambient shelf stability over 6 months. The comprehensive results validate the photovoltaic potential of these earth abundant, sustainable chalcogenide perovskites synthesized via scalable low-cost solution methods. Further interface engineering can enable enhanced efficiencies. [ABSTRACT FROM AUTHOR]

Antimony-based perovskites have been recognized for their distinctive optoelectronic attributes, standard fabrication methodologies, reduced toxicity, and enhanced stability. The objective of this study is to systematically investigate and enhance the performance of all-inorganic solar cell architectures by integrating Cs3Sb2I9, a perovskite-analogous material, with WS2—a promising transition metal dichalcogenide—used as the electron transport layer (ETL), and Cu2O serving as the hole transport layer (HTL). This comprehensive assessment extends beyond the mere characterization of material attributes such as layer thickness, doping levels, and defect densities, to include a thorough investigation of interfacial defect effects within the structure. Optimal efficiency was observed when the Cs3Sb2I9 absorber layer thickness was maintained within the 600-700 nm range. The defect tolerance for the absorber layer was identified at 1×1015/cm3, with the ETL and HTL layers exhibiting significant defect tolerance at 1×1016/cm3 and 1×1017/cm3, respectively. Furthermore, this study calculated the minority carrier lifetime and diffusion length, establishing a strong correlation with defect density; a minority carrier lifetime of approximately 1 µs was noted for a defect density of1×1014/cm3 in the absorber layer. A noteworthy finding pertains to the balance between the high work function of the back contact and the incorporation of p-type back surface field layers, revealing that interposing a highly doped p+ layer between the Cu2O and the metal back contact can elevate the efficiency to 21.60%. This approach also provides the freedom to select metals with lower work functions, offering a cost-effective advantage for commercial-scale applications.

The production of solar panels is continuously increasing due to increasing demands at industrial and residential levels. This also leads to an increasing demand for solar simulator testing tools. A solar simulator is a tool to assess a solar panel's performance in lab and industry scales. One of the main components of the solar simulator is the Air Mass Filter (AMF). The primary function of AMF is to remove unwanted wave bands from the solar simulator light source (e.g., Xe arc lamp) so that the filtered spectrum is commensurate to that of solar irradiation. An AMF can be produced by fabricating a thin material layer on a transparent substrate like glass. The film would absorb certain wave bands in different ways. This paper reports the fabrication of the chalcogenide PbS thin films for applying AMF. The thermal evaporation technique is used for the film fabrication. PbS is known for its versatility for applications in different optical devices due to its tailorable optical properties. Different amounts (in grams) of PbS source powders are used to deposit the PbS thin films. The optical properties of the films are then examined using UV-Vis spectroscopy. The distributions of the transmittance intensity of the Xearc-lamp light with and without the use of the films as an optical filter are then examined using a solar simulator. From the experiments, the film deposited using a 0.012 g PbS powder source is regarded as the optimum one regarding the transmittance intensity distribution. [ABSTRACT FROM AUTHOR]

In this review, we first focus on summarizing recent advances in effective and facile strategies for the ration synthesis of noble metal chalcogenide nanomaterials (NMCNs), and then, we systematically introduce their applications in catalyzing typical electrochemical reactions. Finally, we make some perspectives on the challenges for using NMCNs in electrocatalysis with respect to further enhancement of their electrocatalytic performance. [ABSTRACT FROM AUTHOR]

The study is dedicated to the investigation of thermo-physical characteristics of Se95Te5 chalcogenide glassy semiconductor during its glass formation and crystallization processes, employing various scanning rates of 5, 10, 15 and 20 K/min in non-isothermal modes through DSC measurement. Analysis of the structural relaxation kinetics involves the Kissinger's, Augis and Bennett's, as well as Matusita's approaches. Experimental data yield contains the determination of crucial parameters such as glass transition (Tg), crystallization (Tc), and melting temperatures alongside factors like reduced temperature of glass transition (Trg), Hruby's parameter (Kgl), fragility index (Fi), Avrami exponents (n, m), glass transition ((140.24 kJ/mol) and crystallization (Ec = 95.11 kJ/mol) energies, respectively. The results confirm that Se95Te5 chalcogenide system as an efficient glass former. Matusita's method reveals that the crystallization mechanism (n = 2.51, m = 1.9) corresponds to volumetric nucleation with two-dimensional growth. [ABSTRACT FROM AUTHOR]

Highlights The development history and key milestones of ovonic threshold switch (OTS) materials were comprehensively summarized. Combined with the latest advancements of OTS research, the mainstream OTS material systems were systematically introduced. A thorough overview of the prevailing viewpoints regarding the OTS switching mechanisms was presented. Recent progress in OTS devices for applications in 3D memory, self-selecting memory, and neuromorphic computing was summarized.

ABSTRACTSelenium is a chemical element from the chalcogenide group (Oxygen, Sulfur, Selenium and Tellurium), which has been defined as a critical element by the American Physical Society and the Materials Research Society. Indeed, selenium is used abundantly in nanotechnologies but its scarcity on Earth put its sustainability at risk. This review highlights the properties of selenium at the nanoscale and illustrates some of its most important applications in medicine, agriculture, catalysis, opto-electronics, photovoltaics, piezo-electrics and quantum electronics.

Transmittance self-oscillation discovered in amorphous GeSe2 films has attracted considerable interest, while its underlying mechanism remains controversial. We suggest that the oscillation is governed by at least two kinds of changes; one occurs in absorption for thin (∼ 6 μ m) films and the other in refractive-index for thick (∼ 1 mm) plates. We also detail a model, which assumes recoverable micro-crystallization. An idea for increasing the oscillation frequency is proposed for possible applications. [ABSTRACT FROM AUTHOR]

The rare‐earth chalcogenide Er2Te3, characterized by its low lattice thermal conductivity, represents a highly promising and innovative thermoelectric material. However, there have been limited studies exploring its thermoelectric properties in depth. Additionally, it has been discovered that strain engineering is an effective method for enhancing thermoelectric properties, a technique successfully applied to relevant materials. In this study, we employed a first‐principles approach in conjunction with the semi‐classical Boltzmann transport theory to investigate the thermoelectric properties of Er2Te3 materials under −4% to 4% strain. The results indicate that applying compressive strain modulates thermoelectric properties more effectively than tensile strain for Er2Te3. Under strain modulation, the maximum power factor for both p‐type and n‐type Er2Te3 increases significantly, from 0.9 to 2.5 mW m−1 K−2 and from 14 to 18 mW m−1 K−2 at 300 K, respectively. Moreover, the figure of merit (ZT) for p‐type and n‐type Er2Te3 improves notably, from 0.15 to 0.25 and from 1.15 to 1.35, respectively, under −4% strain. Consequently, the thermoelectric properties of Er2Te3 materials can be significantly enhanced through strain application, with n‐type Er2Te3 demonstrating substantial potential as a thermoelectric material. [ABSTRACT FROM AUTHOR]

In the study, nickel telluride and molybdenum dopants were synthesised using an electrochemical deposition approach. The nanoparticle of the material shows the reaction between the transition metal and chalcogenide material, and the nickel telluride pristine demonstrates that the film surface provides a clean image of melted wax with splattered evidence of oil on the film. The film that was deposited at 0.1 mol% clearly shows how the dopant changed the melted wax to nanoparticles, demonstrating the compatibility of the two materials. The structural patterns showed diffraction peaks at the (111), (200), (210), (211), (300), and (311) diffraction planes, which are equivalent to 13.22 °, 16.95 °, 18.85 °, 25.93 °, 30.84 °, and 32.98 ° for nickel telluride and 13.38 °, 16.93 °, 19.02 °, 25.95 °, 30.85, and 33.02 ° for molybdenum-doped nickel telluride. Both nickel telluride and molybdenum-doped nickel telluride materials produced similar peaks. When the dopant was added, the thickness of the molybdenum-doped nickel telluride films grew from 132.02 to 147.57 nm. The UV area of the spectra was found to have the maximum absorbance and reflectance, however, the transmittance increased as the wavelength of the incident radiation increased. The absorbance, transmittance, and reflectance of nickel telluride and molybdenum-doped nickel telluride thin film material are improved by the addition of molybdenum as a dopant. The energy bandgap of the synthesised films; the nickel telluride has 1.18 eV, while the doped nickel telluride has an energy bandgap of 1.50–1.55 eV which shows that the energy bandgap narrows as molybdenum-dopant concentration rises. [ABSTRACT FROM AUTHOR]

We report the structural characterization of a new quaternary telluride, Ba2Y0.87(1)Mn1.71(1)Te5, which was synthesized by the direct reaction of the elements inside a vacuum‐sealed fused‐silica tube. The quaternary phase is the first member of the Ba–M–Mn–Te system (M = Sc and Y). The composition and structure of the phase were elucidated using SEM–EDX (scanning electron microscopy–energy dispersive X‐ray spectrometry) and single‐crystal X‐ray diffraction (SCXRD) studies. The title phase is nonstoichiometric and crystallizes in the monoclinic system (space group C2/m) having the refined unit‐cell parameters a = 15.1466 (8), b = 4.5782 (3), c = 10.6060 (7) Å and β = 116.956 (2)°, with two formula units (Z = 2). The pseudo‐two‐dimensional crystal structure of Ba2Y0.87(1)Mn1.71(1)Te5 consists of distorted YTe6 octahedra and MnTe4 tetrahedra as the building blocks of the structure. The YTe6 octahedra are arranged to form infinite one‐dimensional chains by sharing edges along the [010] direction. These chains are further connected to the MnTe4 tetrahedra along the c axis to create layered two‐dimensional polyanionic [Y0.87(1)Mn1.71(1)Te5]4− units. The stuffing of Ba2+ cations in between the layers of [Y0.87(1)Mn1.71(1)Te5]4− anions brings the charge neutrality of the structure. Each Ba atom in the structure sits at the centre of a distorted monocapped trigonal prism‐like polyhedron of seven Te atoms. [ABSTRACT FROM AUTHOR]

Reactions of atomic uranium cations with carbon disulfide form US+ in an efficient exothermic reaction and UCS+ in an inefficient endothermic process. The subsequent reaction of US+ with CS2 forms US2+ in an endothermic process having a low energy threshold. At much higher energies, UCS2+ and UCS+ are also formed. Collision-induced dissociation of US+ with Xe yields U+ + S exclusively in an endothermic reaction. Analysis of the kinetic energy dependent cross sections of the endothermic processes yields the 0 K bond dissociation energies of 5.73 ± 0.15 eV for U+ – S, 3.89 ± 0.08 eV for SU+ – S, 1.69 ± 0.17 eV for U+ – CS, 2.78 ± 0.33 eV for U+ – CS2, 1.53 ± 0.30 eV for SU+ – CS, and 5.65 ± 0.39 eV for S – UCS+. Theory is used to explore the structures and electron configurations of US+, US2+, UCS+, and UCS2+. The thermochemistry measured in this study is further compared to analogous values previously determined for select group 3 metals, lanthanides, and actinides. [ABSTRACT FROM AUTHOR]

Reactions of atomic uranium cations with carbon disulfide form US+ in an efficient exothermic reaction and UCS+ in an inefficient endothermic process. The subsequent reaction of US+ with CS2 forms US2+ in an endothermic process having a low energy threshold. At much higher energies, UCS2+ and UCS+ are also formed. Collision-induced dissociation of US+ with Xe yields U+ + S exclusively in an endothermic reaction. Analysis of the kinetic energy dependent cross sections of the endothermic processes yields the 0 K bond dissociation energies of 5.73 ± 0.15 eV for U+ – S, 3.89 ± 0.08 eV for SU+ – S, 1.69 ± 0.17 eV for U+ – CS, 2.78 ± 0.33 eV for U+ – CS2, 1.53 ± 0.30 eV for SU+ – CS, and 5.65 ± 0.39 eV for S – UCS+. Theory is used to explore the structures and electron configurations of US+, US2+, UCS+, and UCS2+. The thermochemistry measured in this study is further compared to analogous values previously determined for select group 3 metals, lanthanides, and actinides. [ABSTRACT FROM AUTHOR]

We report the structural characterization of a new quaternary telluride, Ba2Y0.87(1)Mn1.71(1)Te5, which was synthesized by the direct reaction of the elements inside a vacuum‐sealed fused‐silica tube. The quaternary phase is the first member of the Ba–M–Mn–Te system (M = Sc and Y). The composition and structure of the phase were elucidated using SEM–EDX (scanning electron microscopy–energy dispersive X‐ray spectrometry) and single‐crystal X‐ray diffraction (SCXRD) studies. The title phase is nonstoichiometric and crystallizes in the monoclinic system (space group C2/m) having the refined unit‐cell parameters a = 15.1466 (8), b = 4.5782 (3), c = 10.6060 (7) Å and β = 116.956 (2)°, with two formula units (Z = 2). The pseudo‐two‐dimensional crystal structure of Ba2Y0.87(1)Mn1.71(1)Te5 consists of distorted YTe6 octahedra and MnTe4 tetrahedra as the building blocks of the structure. The YTe6 octahedra are arranged to form infinite one‐dimensional chains by sharing edges along the [010] direction. These chains are further connected to the MnTe4 tetrahedra along the c axis to create layered two‐dimensional polyanionic [Y0.87(1)Mn1.71(1)Te5]4− units. The stuffing of Ba2+ cations in between the layers of [Y0.87(1)Mn1.71(1)Te5]4− anions brings the charge neutrality of the structure. Each Ba atom in the structure sits at the centre of a distorted monocapped trigonal prism‐like polyhedron of seven Te atoms. [ABSTRACT FROM AUTHOR]

Abstract In this review, we first focus on summarizing recent advances in effective and facile strategies for the ration synthesis of noble metal chalcogenide nanomaterials (NMCNs), and then, we systematically introduce their applications in catalyzing typical electrochemical reactions. Finally, we make some perspectives on the challenges for using NMCNs in electrocatalysis with respect to further enhancement of their electrocatalytic performance.

The optically gated transistor (OGT) has been previously demonstrated as a viable selector device for memristor devices, and may enable optical addressing within cross-point arrays. The OGT current–voltage response is similar to a MOSFET device, with light activating the gate instead of voltage. The OGT also provides a naturally built-in compliance current for a series resistive memory element, determined by the incident light intensity on the gate, thus keeping the integrated periphery circuitry size and complexity to a minimum for a memory array. The OGT gate comprises an amorphous Ge2Se3 material that can readily be doped with other elements to alter the transistor’s electrical properties. In this work, we explore the operation of the OGT when the Ge2Se3 gate material is doped with the Group IVA elements C, Si, Sn, and Pb. The dopant atoms provide changes to the optical and electrical properties that allow key electrical properties such as the dark current, photocurrent, switching speed, and threshold voltage to be tuned.

In this paper, 4 × 2 encoder is proposed by combining optical waveguides and the ring resonators. The proposed structure has four input ports, two control input and two output ports. The hexagonal photonic crystal structure has the square lattice of chalcogenide glass rods with the refractive index of 2.1 in air. Maximum bit rate of 10 Tb/s and response time of 0.1 ps is obtained using the proposed cross-layered arrangement of the chalcogenide glass rods with circular inner arrangement. The size of the proposed structure is 18.6 µm x 24.6 µm. Moreover, the contrast ratio of outputs is found to be 28.3 and 48.45 dB. The fundamental structure for the proposed encoder is also designed and analysed for validating the desired bandgap at the resonant wavelength of 1550 nm. [ABSTRACT FROM AUTHOR]

Metal chalcogenides are an inexpensive and abundantly available candidate for catalytic applications. MoS 2 is one among the promising material that has been widely accepted for efficiently facilitating hydrogen evolution reaction (HER) due to the existence of rich edge active sites. However, aggregation of nanoparticles limits their electrochemical activities. Thus, to enhance the catalytic behaviour, functionalization with NiS 2 and rGO is established so that the number of active sites for H absorption will be increased. Further, the heteroatom doping on the pristine rGO alters the electronic structure and facilitate HER. Consequently, MoS 2 /NiS 2 functionalized N-doped rGO as an electrocatalyst manifested superior activity in catalyzing hydrogen evolution. An overpotential of about 164 mV for a current density (10 mA cm−2) in an acidic medium has proven the potential of the novel candidate to be highly promising. The same catalyst also displayed good stability for a longer time period of HER activity with no degradation of the catalyst. These findings affirm that MoS 2 /NiS 2 @N- doped rGO electrocatalyst is a promising candidate for hydrogen production using water electrolyzer. [Display omitted] • Morphologically tuned MoS 2 nanostructures and MoS 2 /NiS@N-rGO composite is developed. • Electrocatalyst MoS 2 /NiS@N-rGO showed superior performance in catalyzing HER. • Existence of more active sites from layered structures facilitated the catalytic activity. • The same catalyst exhibited good endurance in acidic medium. [ABSTRACT FROM AUTHOR]

We fabricated a core-cladding Ge–Sb–Se glass fiber with a Ge12.5Sb15Se72.5 core and Ge15Sb10Se75 cladding, achieved a supercontinuum spectrum spanning from 2 μm to 9 μm by pumping the Ge–Sb–Se fiber with a core diameter of 11 μm using a femtosecond laser pump at 3.8 μm, and numerically simulated the supercontinuum generation using the generalized nonlinear Schrödinger equation. In particular, we investigate the effect of the different Raman response functions that were calculated using the traditional single Lorentzian model and a multiple vibrational mode model on the evolution of the supercontinuum by comparing the supercontinua obtained from simulation and experimental results. We demonstrate that the Raman response function generated by the multiple vibrational mode model captures the actual response behavior of the material, and the supercontinuum generated using this model has more accuracy. To the best of our knowledge, this is the first reported study on supercontinuum generation in Ge–Sb–Se fiber utilizing a Raman response function calculated using the multiple vibrational mode model. This significant advancement enables more accurate simulation of supercontinuum generation in fibers with a multi-peaked structured Raman gain spectrum and holds great potential for optimizing the performance of various mid-infrared supercontinuum sources. [ABSTRACT FROM AUTHOR]

Tellurium oxides of the ATeO3 form typically do not crystallize in perovskite structures. Here, we show that perovskite-like ATeO3 (A = Ca, Sr, Ba) thin films can be grown on perovskite single-crystal substrates via epitaxial stabilization. These films are stable with high optical bandgaps, low dielectric losses, and a high electric breakdown strength. Hysteretic dielectric behavior found in SrTeO3 and BaTeO3 strongly suggests the presence of antiferroelectricity and ferroelectricity, respectively. These properties make perovskite tellurium oxides possibly appealing candidates for thin film coating or insulator materials in advanced microelectronics. Tellurium oxides constitute a largely unexplored class of materials that might show new and interesting functionalities in epitaxial thin-films. Our work encourages new work within this field. [ABSTRACT FROM AUTHOR]

This work exhibits a new theoretical approach about a 2T Tandem solar cell made of two cells: CFTS/Si. For maximum benefit, careful consideration must be given to the selection and performance enhancement of both cells. In order to achieve good results, the bottom and top cells are independently analyzed and optimized to set the best structure for each one of them. Two terminal tandem solar cells are very effective in converting energy. However, one of the main limitations of the 2T terminals model is the circulation of the lowest current density since it is similar to an electric series connection between the sub cells. In this paper we tried to define a current matching point with a good current density. The two SC structures (Top and Bottom) under investigation generated impressive performances of about 24.06% and 22.04%, respectively. The evaluation of the tandem Cu2FeSnS4-on-c-Si solar cell produced the following simulation results: Voc= 1.81 V, Jsc= 22.22 mA/cm2, and Fill Factor=87.61% with a conversion efficiency of 35.23 %. The results demonstrate a thorough analysis of both prospective single-cell performance parameters and tandem device architecture. [ABSTRACT FROM AUTHOR]

Thin films of SnS2 were synthesized by spin coating technique at room temperature using an aqueous solution of stannic chloride and thioacetamide as the absorber layer in solar cells. The films were deposited at different spin speeds and spin times, and their effect on the properties of the thin films was studied. The spin speed was varied from 1000 to 2000 rpm, and the spin time was from 60 to 120 s for each speed. The structure of the films was found to be face-centered cubic with preferential orientation along the (002) plane; there was no sign of other unwanted phases. With increasing spin speeds and deposition times, the crystallinity of the sample was improved for a certain speed, after that, it deteriorated crystallinity. FTIR peaks confirmed the presence of Sn–S bonds in all the prepared films. Morphological results of the films were consisting of small spherical grains in an aggregated form that is abated by spin speed. EDAX revealed that the thin film was found near stoichiometric and some excess amount of tin was present in the sample. Atomic force microscopy showed the presence of grains, hills, and valleys on the surfaces of thin films. XPS results confirmed the presence of Sn and S in the deposited films. The band gap values for the films deposited at 1500 rpm for 90 s calculated from the absorbance spectra increased from 2.9 to 3.5 eV with an increase in deposition time attributed to a change in film thickness. [ABSTRACT FROM AUTHOR]

In this work, the structural polymorphism and electro-optical characteristics of NaSbS2 ternary chalcogenide are realized using density functional theory (DFT). All of the NaSbS2 polymorphs are energetically stable based on the formation energy. The optimized lattice parameters of the monoclinic and triclinic structures and direct electronic bandgap (1.695 eV) of monoclinic structure are consistent with previous studies. Besides, the trigonal and triclinic structures are indirect bandgap (0.916 and 2.015 eV) semiconductors observed from electronic band structure. The higher degree of ionicity between Na and S atoms while strong covalency in the Sb-S bonds are confirmed from the charge and bond analysis. The lower value of electron-hole effective masses indicates higher carrier mobility leading to outstanding electrical conductivity. It was suggested that the polymorphs would be extremely desired to design Bragg reflectors and waveguides based on the reported high value of the real part of the dielectric constant and refractive index. These polymorphs will contribute significantly to being used as absorbers, as evidenced by their high absorption coefficient and photoconductivity and lower transmittance. All the polymorphs reflect significant optical anisotropy and birefringence, rendering them excellent for usage in the fabrication of waveguides, polarizers, and photonic devices. Thus, the projected good features of NaSbS2 polymorphs would play an essential role in the development of lead-free photovoltaic devices, including solar cells and other optoelectronic devices, and would be able to provide practical information for future theoretical and experimental studies.

This study used electrochemical deposition to make CeTe and CeTe-doped molybdenum. We deposited the films at varying concentrations of the dopant; (0.1–0.3) mol%. All the solutions used to deposit the thin films were prepared in distilled water. Adding molybdenum to cerium telluride boosts absorption rates. Film thickness decreased from 117.09 to 164.31 nm, lowering resistivity (11.24 to 08.23 ῼ.cm) and increasing conductivity (0.08 to 0.12 S/m). The pattern exhibit diffraction peaks at planes (111), (120), (121), and (131), which correspond to respective angles of 23.216°, 27.744°, 32.152°, and 36.182° The FTO substrates used for the synthesis may have been the cause of the unindexed peaks. The bandgap energy of cerium telluride is 1.20 eV, which narrows to 1.49 – 1.60 eV as molybdenum dopant concentration rises. The cerium telluride and CeTe-doped molybdenum have a lattice constant of 6.6490 and 6.6298 Å respectively. Cerium telluride doped molybdenum is a potential candidate for photovoltaic application.

Chalcogenide based nano‐films have attracted considerable attention as a new type of semiconductor material in the fields of optical waveguides, laser devices, and solar cells. However, it remains challenging to use them effectively in a variety of fields, mainly due to their intricate fabrication procedures and limited electrical characteristics. In this study, zinc selenide (ZnSe) is doped with molybdenum (Mo) and gallium (Ga). The heterodimensional structured chalcogenide semiconductor nano‐film is obtained by pulsed laser deposition (PLD). The results of scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) confirm that the structure of the nano‐film is compact and the composition is uniformly distributed. The transmittance of all samples is close to 100% in the 400–2000 nm range shown. The P/N type of the film can be controlled by changing the preparation conditions. All the results indicate that the novel heterodimensional structured chalcogenide semiconductor nano‐film in this study has a simple and efficient preparation method, controllable composition, and unique optical/electrical properties. These properties can be used in integrated circuits and photovoltaic power generation. [ABSTRACT FROM AUTHOR]

Our calculations of the global instability index (G) values for some diamond‐like materials with the general formula I2–II–IV–VI4 have indicated that the structures may be unstable or incorrectly determined. To compute the G value of a given compound, the bond valence sums (BVSs) must first be calculated using a crystal structure. Two examples of compounds with high G values, based on data from the literature, are the wurtz–stannite‐type dicopper cadmium silicon tetrasulfide (Cu2CdSiS4) and the stannite‐type dicopper mercury tin tetrasulfide (Cu2HgSnS4), which were first reported in 1967 and 1965, respectively. In the present study, Cu2CdSiS4 and Cu2HgSnS4 were prepared by solid‐state synthesis at 1000 and 900 °C, respectively. The phase purity was assessed by powder X‐ray diffraction. Optical diffuse reflectance UV/Vis/NIR spectroscopy was used to estimate the optical bandgaps of 2.52 and 0.83 eV for Cu2CdSiS4 and Cu2HgSnS4, respectively. The structures were solved and refined using single‐crystal X‐ray diffraction data. The structure type of Cu2CdSiS4 was confirmed, where Cd2+, Si4+ and two of the three crystallographically unique S2− ions lie on a mirror plane. The structure type of Cu2HgSnS4 was also verified, where all ions lie on special positions. The S2− ion resides on a mirror plane, the Cu+ ion is situated on a fourfold rotary inversion axis and both the Hg2+ and the Sn4+ ions are located on the intersection of a fourfold rotary inversion axis, a mirror plane and a twofold rotation axis. Using the crystal structures solved and refined here, the G values were reassessed and found to be in the range that indicates reasonable strain for a stable crystal structure. This work, together with some examples gathered from the literature, shows that accurate data collected on modern instrumentation should be used to reliably calculate BVSs and G values. [ABSTRACT FROM AUTHOR]

The rare-earth chalcogenides Y2Te3 with low lattice thermal conductivity is a very promising novel thermoelectric material. Applying strain is an effective way to modulate the thermoelectric properties of thermoelectric materials. In this paper, first-principles approach combined with the semiclassical Boltzmann transport theory were used to study the strain modulation of the thermoelectric properties of Y2 Te3 materials, for which -4% to 4% strain was applied to the Y2 Te3 materials. The results show that applying compressive strain may modulate thermoelectric properties more effectively than tensile strain. The maximum power factor of p-type Y2Te3 increases from 0. 4 mW⋅m-1 ⋅K-2 to 1. 6 mW ⋅m-1 ⋅ K-2 at 300 K, and the maximum power factor of n-type Y2Te3 increases from 8 mW ⋅ m-1 ⋅ K-2 to 11 mW ⋅ m-1 ⋅ K-2 under compressive strain. The maximum thermoelectric figure of merit (ZT) of p-type Y2Te3 increases from 0. 07 to 0. 15 under strain modulation at 300 K, and the maximum ZT of n-type Y2Te3 increases from 0. 7 to 0. 9 under compressive strain. Therefore, n-type Y2Te3 has very excellent thermoelectric properties, and the thermoelectric properties of Y2Te3 materials can be effectively regulated by applying strain. n-type Y2Te3 has great potential as a thermoelectric material. [ABSTRACT FROM AUTHOR]

Barium zirconium sulfide (BaZrS3), a chalcogenide perovskite, is attracting a lot of attention for thin‐film photovoltaic (PV) application. Unlike the lead halide perovskites, it is stable and does not contain toxic elements. Herein, PV devices incorporating barium zirconium sulfide (BZS) are investigated numerically as a photoabsorber with a back‐contact layer of both crystalline and amorphous p+ type silicon, using a Solar Cell Capacitance Simulator software‐1D. The titanium (Ti) alloyed BZS, which has an electron‐energy bandgap close to optimum for a single junction PV device, is also investigated. A systematic study is carried out by varying the thickness, doping density, and defect density in the BZS layer. Among the two phases of Si, the amorphous one results in higher photoconversion efficiency (PCE) due to a favorable energy band alignment with BZS. The corresponding best PCEs predicted from the study are 19.7% for BZS films and 30% for Ba(Zr0.95Ti0.05)S3 films with the amorphous Si as back‐contact. [ABSTRACT FROM AUTHOR]

The newly discovered ternary chalcogenide superconductor Bi2Rh3Se2 has attracted growing attention, which provides an opportunity to explore the interplay between charge density wave (CDW) order and superconductivity. However, whether the phase transition around 240 K can be attributed to the formation of CDW remains controversial. To help resolve the debate, we study the electronic structure of Bi2Rh3Se2 by angle-resolved photoemission spectroscopy, focusing on the nature of its high-temperature phase transition around 240 K. Our measurements demonstrate that the phase transition at 240 K is a second-order CDW phase transition. Our results reveal (i) a 2 × 2 CDW order in Bi2Rh3Se2, accompanied by the reconstruction of electronic structure, such as band folding, band splitting, and opening of CDW gaps at and away from the Fermi level; (ii) the existence of electron-boson coupling, which is manifested as an apparent kink and peak-dip-hump structure in dispersion. Our observations thus enable us to shed light on the nature of CDW order and superconductivity in Bi2Rh3Se2. [ABSTRACT FROM AUTHOR]

We report the fabrication of a semiconductor thin layer of ternary chalcogenide, Ge33Se47Sn20, utilizing a thermal evaporation technique for optical applications. The chemical composition and crystal structure studies on Ge33Se47Sn20 thin films were carried out by energy-dispersive x-ray and x-ray diffraction measurements. The effect of ultraviolet (UV) irradiation on the linear and nonlinear optical properties of the Ge33Se47Sn20 thin films has been investigated from the UV–Visible spectra. The studied optical parameters of the virgin and UV-irradiated Ge33Se47Sn20 thin films were found to be strongly dependent upon UV irradiation time. The changes in the optical band gap of the Ge33Se47Sn20 thin films upon UV irradiation are due to bonding rearrangements. The significant changes in linear/nonlinear optical parameters with UV irradiation are useful for linear/nonlinear optical applications. [ABSTRACT FROM AUTHOR]

This work aimed to synthesize, characterize and evaluate the thermal stability of new sulfur and selenium organochalcogenide derivatives and to test the cytotoxic activity against breast adenocarcinoma cell line (MCF-7) through conducting MTT assay and AO/EB dual staining-technique. Two series of ten organo-chalcogen compounds: 4-(substituted)phenylthiomorpholine-3,5-dione and 4-(substituted)phenylselenomorpholine-3,5-dione were prepared by the reaction of Na2S·3H2O and NaHSe with N-(substituted)phenyl-2-chloro-N-(2-chloroacetyl)acetamide, respectively, under nitrogen atmosphere to give the corresponding cyclic chalcogenide ligands. All new compounds were characterized by melting point, FTIR, elemental analysis, UV-Visible, 1H-NMR and 13C-NMR. Meanwhile, TG/DTA analysis of some of these ligands was conducted to evaluate the thermal stability, kinetic, and characteristic thermodynamic parameters. Absorption spectroscopy was used to investigate these compounds with human DNA. The experimental results investigated a hypochromic effect via intercalation binding mode. The role of the prepared ligands in breast cell lines has been investigated by conducting MTT assay via spectroscopic techniques on HBL100 and MCF-7, normal and cancer breast cell lines, respectively. Cell death was seen after AO/EB dye staining method employing the fluorescence microscopy technique. The results revealed that these compounds possess cytotoxic activity on the MCF-7 and HBL-100 cell lines at a fixed concentration.

Selenium-rich chalcogenides have gained popularity as materials for selector devices due to their unique Ovonic Threshold Switching behavior. Bulk Se 86-x Te 14 Sn x glassy alloys (0 ≤ x ≤ 6) were prepared through the traditional melt quenching method. The samples with Sn atomic percentage (x) = 3 to 6 are found to exhibit a rapid and reversible transition between a highly resistive and conductive state affected by an electric field. A remarkable decrement in threshold voltage (V th) from 453 V to 62 V has been observed with increase in the Tin content. Differential scanning calorimetry (DSC) analysis was carried out to understand the variation of Glass transition temperature (T g), Crystallization temperature (T c), and other important glass stability parameters and their compositional dependence. Se 82 Te 14 Sn 4 sample was found to be thermally most stable with Herby's parameter value (H R) of 0.3860 and a maximum number of switching cycles at room temperature. X-Ray diffraction patterns of annealed samples were compared with pristine glass to study the multi-phasic Se–Te–Sn alloy. Further, the threshold voltage (V th) and the number of threshold switching cycles are found to decrease with an increase in temperature till crystallization on-set temperature (T oc). The temperature-dependent conductivity studies showed an abrupt increase in the conductivity of the samples as the temperature crossed the crystallization onset temperature. [Display omitted] • Se 86-x Te 14 Sn x (0 ≤ x ≤ 6) samples synthesized through the melt-quenching method. • Threshold type of switching was observed for all the synthesized glasses. • DSC studies revealed that the Se 82 Te 14 Sn 4 sample is thermally most stable. • The most stable Se 82 Te 14 Sn 4 sample sustained the highest number of switching cycles. • Annealing studies confirmed the formation of multiphasic crystalline material. [ABSTRACT FROM AUTHOR]