Search Results (105)

In this study, we combined lead-free inorganic perovskite, CsSnI₃, with a transition metal chalcogenide, MoS₂, to develop a hybrid architecture for photodetectors utilizing the SCAPS-1D simulation tool. The performance of the photodetector was investigated across various thicknesses, doping concentrations, light intensities, and temperatures. An in-depth analysis of built-in potential, recombination rate, generation rate, quantum efficiency, I-V characteristics, and other performance parameters showed that the ideal thickness, doping density, bulk defect density, and interface defect density for enhanced photodetector performance are 800 nm, 1 × 10¹⁹ cm⁻³, 1 × 10¹⁴ cm⁻³, and 1 × 10¹⁰ cm⁻³, respectively. The photodetector exhibits optimal performance within the wavelength range of 200–500 nm and under illumination levels of 500–700 mW/m², maintaining a consistent responsivity of 0.59 A/W, a detectivity of 4.28 × 10¹³ Jones, a photocurrent of 34.50 mA/cm², and a low dark current of 10⁻⁶ mA/cm², with good thermal stability over a wide range of temperatures. The findings indicate that the CsSnI₃/MoS₂ heterojunction photodetector exhibits superior performance characterized by enhanced sensitivities throughout a broad operational range within the UV–blue visible spectrum and paves the way for the development of cost-effective, high-performance photodetectors in future optoelectronic applications. Full article

The self-directed channel (SDC) class of memristors employs a multilayer architecture that is designed to enable robust Ag ion conduction, long cycling lifetime, and thermal stability. While several layers contribute to mechanical and chemical reliability, two layers primarily govern the electrical behavior: the amorphous Ge–chalcogenide active layer that is adjacent to the bottom electrode and the overlying metal–chalcogenide source layer. In this work, we investigate how the variation in the chalcogen species in these two layers influences switching characteristics in the pre-write regime, both in the pristine state and after a write/erase cycle, as well as the conduction behavior at room temperature. The devices were fabricated using Ge-rich chalcogenides containing O, S, Se, or Te, combined with SnS, SnSe, or Ag₂Se metal–chalcogenide layers. The DC current-voltage measurements were analyzed using the standard linearization approaches to examine whether the transport behavior in the pre-write regime exhibits characteristics that are associated with Ohmic, Schottky, Poole–Frenkel, or space charge limited conduction. These measurements specifically probe the pre-write region of the I-V curve, where early ionic redistribution and structural rearrangement precede the abrupt formation of the conductive channels responsible for the resistive switching. The results show that the chalcogen composition strongly affects the threshold voltage, the resistance window, and the onset of field-enhanced transport, reflecting the differences in ionic distribution and channel formation dynamics. The results indicate that transport evolves with a bias and a compliance current, transitioning between regimes that are influenced by the interface injection and bulk-limited conduction, depending on the material stack. These findings clarify the role of chalcogen chemistry in governing the SDC switching behavior and provide guidance for the material selection in application-specific device design. Full article

Murunskite (K₂FeCu₃S₄) is a layered sulfosalt chalcogenide that occupies a unique position between the cuprate and iron pnictide families: it shares electronic characteristics with the former and adopts the crystal structure of the latter. Despite a completely random distribution of magnetic Fe within a nonmagnetic Cu matrix, murunskite exhibits a well-defined quarter-zone antiferromagnetic transition at 97 K and complete orbital order below 30 K. These findings reveal the unexpected emergence of long-range order in a high-entropy-like environment. This inherent robustness to site disorder in a layered structure makes murunskite a paradigmatic system for further studies. Here, we investigate doping strategies in murunskite to assess how its electronic and magnetic properties can be tuned. Using melt-growth techniques, we achieve substitutions at the magnetic metal site (Fe), spacer cation (K), and sulfur ligand (S), which significantly influence transport and magnetic properties. In addition, we use ionic-liquid gating on the parent compound and observe a gate-dependent suppression of resistivity, confirming the potential for electrostatic control over transport. Our results demonstrate the chemical and electronic plasticity of murunskite, offering a valuable platform for co-engineering disorder, magnetism, and transport, and opening avenues to explore quantum phenomena in correlated and high-entropy materials. Full article

Heterointerface engineering, especially the construction of heterointerfaces based on two highly active components, is an effective strategy to enhance the sodium storage capacity and accelerate the reaction kinetics of transition metal chalcogenide anodes. Herein, a series of SA-CoFe-S composites composed of two highly active metal sulfides, Co₃S₄ and Fe₇S₈, were fabricated through in situ chelation effects coupled with a one-step sulfurization strategy. The optimized SA-CoFe(1:4)-S is composed of fine nanoparticles encapsulated by uniformly distributed S-doped carbon. This unique carbon confinement effect and nano-sized active particles can alleviate volume expansion, shorten the ion diffusion distance, and accelerate electron transfer. In addition, the strong electric-field effect and rich heterointerfaces generated by the heterostructure provide more active sites for sodium storage and accelerate the sodium storage kinetics. The relevant theoretical calculation outcomes further confirm that the heterointerfaces formed between Co₃S₄ and Fe₇S₈ can enhance the adsorption energy toward sodium ions and boost the electrical conductivity of the composite material. As an anode material for sodium-ion batteries, the initial discharge/charge capacities were 723/1010 mAh·g⁻¹, exhibited at 1 A·g⁻¹, and the coulombic efficiency (CE) corresponding to this current density was measured to be 71.6%. Even after 800 cycles, the reversible discharge specific capacity of the electrode can still reach 806 mAh·g⁻¹ at 1 A·g⁻¹. Additionally, at an elevated current density of 3 A·g⁻¹, the electrode sustains stable cycling over 500 cycles, with its discharge capacity kept at 258 mAh·g⁻¹ after the long-term cycling test. Full article

A novel ternary transition metal chalcogenide Ba₂Re₆Se₁₁, which crystallizes in the R−3c space group, was synthesized using a high-pressure and high-temperature technique. The lattice is constituted by Re₆Se₈ cube-octahedral clusters connected by additional apical Se anions via the Re-Se-Re pathway, while the Ba atoms reside in the cavities among the Re₆Se₈ units. High-pressure synchrotron X-ray diffraction measurements showed that Ba₂Re₆Se₁₁ maintains a trigonal structure up to a pressure of 60 GPa, with a bulk modulus of 193 GPa. The lattice stability is ascribed to the fully occupied valence bands of the molecular orbital of the Re₆Se₈ cluster with trivalent Re. This fully occupied orbital configuration also gives rise to the diamagnetic state of Ba₂Re₆Se₁₁, which was validated through magnetic measurements. The resistivity of Ba₂Re₆Se₁₁ is as low as several milliohm centimeters, and it follows the thermal activation mechanism at elevated temperatures and the three-dimensional variable-range hopping model at low temperatures, indicating that Ba₂Re₆Se₁₁ is a semiconductor or insulator in close vicinity to a metal–insulator transition. Full article

Magnesium–sulfur (Mg-S) batteries represent a novel category of multivalent energy storage systems, characterised by enhanced theoretical energy density, material availability, and ecological compatibility. Notwithstanding these benefits, the practical implementation of this approach continues to be hindered by ongoing issues, such as polysulfide shuttle effects, slow Mg²⁺ transport, and significant interfacial instability. This study emphasises recent progress in utilising transition metal chalcogenides (TMCs) as cathode materials and modifiers to overcome these challenges. We assess the structural, electrical, and catalytic characteristics of TMCs such as MoS₂, CoSe₂, WS₂, and TiS₂, highlighting their contributions to improving redox kinetics, retaining polysulfides, and enabling reversible Mg²⁺ intercalation. The review synthesises results from experimental and theoretical studies to offer a thorough comprehension of structure–function interactions. Particular emphasis is placed on morphological engineering, modulation of electronic conductivity, and techniques for surface functionalisation. Furthermore, we examine insights from density functional theory (DFT) simulations that corroborate the observed enhancements in electrochemical performance and offer predictive direction for material optimisation. This paper delineates nascent opportunities in Artificial Intelligence (AI)-enhanced materials discovery and hybrid system design, proposing future trajectories to realise the potential of TMC-based Mg-S battery systems fully. Full article

Lactate is a vital biomarker for disease diagnosis and healthcare management. With the development of wearable sensors, by analyzing biofluids, such as sweat, saliva, and tears, it is possible to implement the in situ detection of lactate, which could provide clinical-grade data for early disease detection and personalized healthcare. Among them, non-enzymatic lactate electrochemical sensors (NELESs) are on the rise due to their quick response, are easily miniaturized, and have the ability to overcome the intrinsic disadvantages of enzymatic sensors. Compared with enzyme-based lactate sensors, NELESs could simplify the electrode preparation process, reduce the cost, and improve the sensing stability and service life. In this review, we introduce the significance of the real-time monitoring of lactate and highlight recent advances in wearable electrochemical sensors toward continuous lactate analysis in biofluids. In particular, metal nanomaterials have great potential in constructing NELESs due to their unique physical and chemical properties, which can be divided into four categories: bimetallic nanomaterials, transition metal chalcogenides (TMC), metal oxides, and layered double hydroxides. We discuss recent advances of these non-enzymatic lactate oxidation materials in detail, and provide some insights for the further development of NELESs through a comprehensive analysis. Full article

This study presents a reconfigurable planar photonic device capable of dynamically switching between optical filter and absorber functionalities by exploiting the phase transition properties of GeTe, a chalcogenide phase-change material. The device adopts a Metal–Dielectric–PCM architecture composed of silver (Ag), silicon dioxide (SiO₂), and GeTe layers, each playing a distinct role: the silver layer governs the transmission and absorption efficiency, the SiO₂ layer controls the resonance conditions, and the GeTe layer determines the device’s scattering behavior via its tunable optical losses. Numerical simulations revealed that the structure enables high RGB transmission in the amorphous state and broadband absorption in the crystalline state. By adjusting geometric parameters—especially the metallic thickness—the device exhibits finely tunable spectral responses under varying polarizations and incidence angles. These findings highlight the synergistic interplay between material functionality and layer configuration, positioning this platform as a compact and energy-efficient solution for applications in tunable photonics, optical sensing, and programmable metasurfaces. Full article

Developing efficient and sustainable hydrogen production technologies is critical for advancing the global clean energy transition. This review highlights recent progress in the design, synthesis, and electrocatalytic applications of MXene-based materials for electrochemical water splitting. It discusses the fundamental mechanisms of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), and the structure–function relationships that govern electrocatalytic behavior. Emphasis is placed on the intrinsic structural and surface properties of MXenes, such as their layered architecture and tunable surface chemistry, which render them promising candidates for electrocatalysis. Despite these advantages, several practical limitations hinder their full potential, including oxidation susceptibility, restacking, and a limited number of active sites. Several studies have addressed these challenges using diverse engineering strategies, such as heteroatom doping; surface functionalization; and constructing MXene-based composites with metal chalcogenides, oxides, phosphides, and conductive polymers. These modifications have significantly improved catalytic activity, charge transfer kinetics, and long-term operational stability under various electrochemical conditions. Finally, this review outlines key knowledge gaps and emerging research directions, including defect engineering, single-atom integration, and system-level design, to accelerate the development of MXene-based electrocatalysts for sustainable hydrogen production. Full article

Highly efficient and stable non-Pt-based electrocatalysts for oxygen reduction reactions (ORRs) are highly desirable in energy conversion and storage systems. Herein, we report a hydrothermally synthesized metal chalcogenide cluster-based framework (NCF-3-Mn), which is decorated with transition metal complexes ([Mn(TEPA)]²⁺, TEPA = tetraethylenepentamine), for an electrocatalytic O₂ reduction reaction (ORR). Benefitting from the abundant Mn-S bonds and Mn-N-C structures in NCF-3-Mn, it was found that NCF-3-Mn displayed a high onset potential (0.90 V) and an efficient four-electron transfer reaction pathway, which are much better than those of its analogue framework (T2-GaSbS). Moreover, NCF-3-Mn also exhibited a considerable long-term stability and methanol resistance toward ORRs. This work will present new opportunities for exploring the utilization of chalcogenide frameworks as novel non-Pt electrocatalysts for ORRs. Full article

To investigate the application potential of amorphous transition metal chalcogenides in catalysis, this study successfully synthesized amorphous molybdenum telluride (MoTe_x) materials and systematically explored their structural characteristics, compositional modulation, and catalytic performance. Experimental results indicate that the synthesized amorphous system consists of particles of approximately 200–300 nm in size. This distinct microstructure facilitates the exposure of abundant active sites and enhances physical adsorption capacity. The amorphous MoTe₂/MoTe₃ catalysts achieve an approximately 30%/40% degradation of methylene blue (MB) within 90 min, demonstrating significantly enhanced photocatalytic efficiency compared to that of crystalline MoTe₂ (≈20% degradation under identical conditions). Furthermore, when integrated with titanium dioxide (TiO₂), the composite exhibits exceptional co-catalytic performance, achieving a 90% degradation of MB within 90 min under visible-light irradiation, representing a catalytic efficiency improvement exceeding 160% compared to the results for pristine TiO₂. Furthermore, through comparative analysis of the catalytic behavior and microstructural variations between amorphous MoTe₃ (a-MoTe₃) and MoTe₂ (a-MoTe₂), we observed that the catalytic activity of molybdenum tellurides exhibits a weak correlation with the tellurium content, with co-catalytic efficacy jointly governed by the density of the active sites and the physical adsorption properties. This research provides new methods and insights for the study and improvement of catalytic performance in chalcogenide materials. Full article

New bulk chalcogenides from the system (GeTe₆)_1−xCu_x, where x = 5, 10, 15 and 20 mol%, have been synthesized. The structure and composition of the materials were studied using X-ray powder diffraction (XRD) and energy-dispersive spectroscopy (EDS). Scanning electron microscopy (SEM) was applied to analyze the surface morphology of the samples. Some thermal characteristics such as the glass transition, crystallization and melting temperature and some physico-chemical properties such as the density, compactness and molar and free volumes were also determined. The XRD patterns show sharp diffraction peaks, indicating that the synthesized new bulk materials are crystalline. The following four crystal phases were determined: Te, Cu, CuTe and Cu₂GeTe₃. The results from the EDS confirmed the presence of Ge, Te and Cu in the bulk samples in concentrations in good correspondence with those theoretically determined. A layered thin-film material based on Ge₁₄Te₈₁Cu₅, which exhibits lower network compactness compared to the other synthesized new chalcogenides, and the azo polymer PAZO was fabricated, and the kinetics of the photoinduced birefringence at 444 nm was measured. The results indicated an increase in the maximal induced birefringence for the layered structure in comparison to the non-doped azo polymer film. Full article

Two-dimensional (2D) materials have revolutionized the field of optoelectronics by offering exceptional properties such as atomically thin structures, high carrier mobility, tunable bandgaps, and strong light–matter interactions. These attributes make them ideal candidates for next-generation photodetectors operating across a broad spectral range—from ultraviolet to mid-infrared. This review comprehensively examines the recent progress in 2D material-based photodetectors, highlighting key material classes including graphene, transition metal dichalcogenides (TMDCs), black phosphorus (BP), MXenes, chalcogenides, and carbides. We explore their photodetection mechanisms—such as photovoltaic, photoconductive, photothermoelectric, bolometric, and plasmon-enhanced effects—and discuss their impact on critical performance metrics like responsivity, detectivity, and response time. Emphasis is placed on material integration strategies, heterostructure engineering, and plasmonic enhancements that have enabled improved sensitivity and spectral tunability. The review also addresses the remaining challenges related to environmental stability, scalability, and device architecture. Finally, we outline future directions for the development of high-performance, broadband, and flexible 2D photodetectors for diverse applications in sensing, imaging, and communication technologies. Full article

Introducing magnetic dopants into topological insulators (TIs) provides a pathway to realizing novel quantum phenomena, including the quantum anomalous Hall effect (QAHE) and axionic states. One of the most commonly used $3d$ transition metal dopants is Mn, despite its known tendency to be highly mobile and to cause phase segregation. In this study, we present a detailed magnetotransport investigation of Mn-overdoped Bi₂Te₃ thin films using field-effect transistor architectures. Building on our previous structural investigations of these samples, we examine how high Mn content influences their electronic transport properties. From our earlier studies, we know that high Mn doping concentrations lead to the formation of secondary phases, which significantly alter weak antilocalization behavior and suppress topological surface transport. To probe the gate response of these doped films over extended areas, we fabricate field-effect transistor structures, and we observe uniform electrostatic control of conduction across the magnetic phase. Inspired by recent developments in intrinsic topological systems such as the MnTe-Bi₂Te₃ septuple-layer compounds, we explore the influence of embedded ferromagnetic chalcogenide inclusions as an alternative route to engineer magnetic topological states and potentially expand the operational temperature range of QAHE-enabled devices. Full article

Chalcogenide samples from the As₂Se₃-GeTe-CdTe system were synthesized by the melt-quench technique. The surface topography of some of the samples was performed with the help of scanning electron microscopy. Various physical parameters of the chalcogenide glasses were calculated: the degree of cross-linking atom, the average heteropolar bond energy of the glasses, the content of chalcogen in the glass, the mean coordination number, and the average energy of the chemical bonds between the atoms of the metals in the glass. With their help, the components of the overall bond energy were calculated: the mean bond energy of the average cross-linking per atom and the average bond energy per atom of the “remaining matrix”. A linear dependence has been established between the glass transition temperature and the overall mean bond energy and between the glass transition temperature and the mean coordination number. The correlation between microhardness and glass transition temperature of chalcogenide glasses was investigated. The dependance between the composition and physical parameters of the As₂Se₃-GeTe-CdTe glasses was established and discussed. Full article