Ternary Chalcogenide Research Articles

Soft template-assisted design and synthesis of anisotropic 2D–3D CuInS2 with a controlled morphology and band gap: exploring photothermal interfacial water evaporation

Synthesizing I–III–VI2 ternary semiconductor chalcogenide nanostructures with precise control over their shape and bandgap is a major focus of current research.

Charge Recombination and Transport Phenomena in Lead-Free Quantum Dot Solar Cells Probed by Impedance Spectroscopy

Due to their unique tunability and solution processability, the implementation of nanoscale semiconductor particles into optoelectronic devices is of increasing interest for future applications.1 Regarding the incorporation into solar cells, one of the most well-studied materials in form of quantum dots (QDs) is lead sulphide.1–3 However, due to its toxicity, replacing lead by a more environmentally friendly material would be immensely advantageous. In that context, ternary metal chalcogenides attracted a lot of interest, as many of them also provide a suitable band gap and high absorbance coefficients. One of the more prominent examples of that material class is AgBiS2.4 It has already been implemented in QD solar cells with remarkably high efficiencies, exceeding 8%.5 Nevertheless, detailed understanding of the charge recombination and transport processes in these devices still needs to be improved, especially with respect to the effect differences in surface passivation have on the aforementioned parameters.At the same time, impedance spectroscopy is a versatile technique that allows to probe the inductive, capacitive and resistive properties of a material or device over a wide range of time scales.6 However, it is a rarely employed method in this specific field of research.Therefore, it has been utilized here to study the recombination and transport properties in AgBiS2 QD solar cells to gain new insights into the underlying dynamics. Additionally, transient photovoltage and photocurrent measurements were employed to obtain an initial model and thus be able to reliably interpret the data from the impedance spectroscopy.As a result, it was found that changing the surface passivating treatment of the AgBiS2 QDs from iodide-containing compounds to bromide or chloride would improve the charge carrier lifetime and recombination resistance, while simultaneously the corresponding transport times exhibited a much less pronounced response. However, there were subtle differences found in the related transport resistances, which give rise to the hypothesis that there might be divergent mechanisms involved or even limiting charge transport depending on the exact surface composition of the QDs.Consequently, this study highlights the crucial importance of understanding the interplay of QD-ligand interaction in those hybrid systems, since it will significantly impact the overall material properties and thereby any device based on it. Furthermore, it demonstrates the suitability and value of employing impedance spectroscopy as a tool to probe for charge transport and recombination processes in this material.References Carey, G. H. et al. Colloidal Quantum Dot Solar Cells. Chem. Rev. 115, 12732–12763 (2015).Brown, P. R. et al. Energy level modification in lead sulfide quantum dot thin films through ligand exchange. ACS Nano 8, 5863–5872 (2014).Liu, M. et al. Hybrid organic-inorganic inks flatten the energy landscape in colloidal quantum dot solids. Nat. Mater. 16, 258–263 (2017).Bernechea, M. et al. Solution-processed solar cells based on environmentally friendly AgBiS2 nanocrystals. Nat. Photonics 10, 521–525 (2016).Wang, Y. et al. Cation disorder engineering yields AgBiS2 nanocrystals with enhanced optical absorption for efficient ultrathin solar cells. Nat. Photonics 16, 396 (2022).Von Hauff, E. Impedance Spectroscopy for Emerging Photovoltaics. J. Phys. Chem. C 123, 11329–11346 (2019).

A Dual-Ion Synergistic Catalysis Utilizing Zn2+-Regulated CdSySe1-y ECL Immunosensor Employed for the Ultrasensitive CA19-9 Detection.

Carbohydrate antigen 19-9 is a well-known malignancy biomarker, and its sensitive detection is particularly crucial in the diagnosis and assessment of pancreatic cancer. In this study, an ultrasensitive CA19-9 immunosensor was constructed using the Zn2+-regulated CdSySe1-y (Zn-CdSySe1-y) nanospheres (NSs) as the electrochemiluminescence (ECL) emitter and FeCoS2 nano octahedrons (NOs) as a coreactant enhancer. The microstructure of ternary transition metal chalcogenide CdSySe1-y was precisely tuned by Zn2+ doping to avoid aggregation and thus enable stable and efficient cathodic ECL responses. The bimetallic sulfide FeCoS2 was synthesized using a metal organic framework (MOF) as the template by ion permeation. It was able to catalyze the coreactant efficiently due to the synergistic effect of the Fe2+ and Co2+. The immunosensor exhibited low detection limit (7.6 × 10-5 U mL-1) in the wide linear range of 0.0001-100 U mL-1, offering a sensitive CA19-9 detection method.

Emerging Bi‐Based Multicationic Ternary Chalcogenides as Promising Photoabsorbers for Solar Cells

Bismuth‐based multicationic chalcogenide solar cells of class ABiX2 (A–Ag, Cu; X–S, Se) have attracted substantial interest within the photovoltaic research community mainly due to their nontoxic nature and rising power conversion efficiencies. Although a good amount of research on these materials is underway, it calls for an intense and comprehensive approach to address the poor performance (PCE 10%) compared to its reported theoretical efficiency of 29%. Hence a review in this direction to address various unexplored concerns of these materials particularly, the defects and unfavorable band positions that give rise to enormous nonradiative recombinations, leading to major voltage losses in these devices is necessary. The article also discusses the structural and electronic properties, deposition techniques, device optimization strategies, impact of grain size, interface engineering, cationic disorder, transport layers, and light‐harvesting techniques that may be required to enhance the device performance. Additionally, a comprehensive analysis of stability and cost considerations of the emerging AgBiS2 solar devices is conducted to unveil their real‐time applications in comparison to current state‐of‐the‐art devices.

Investigating the electronic structure, elastic, optical, and thermoelectric nature of novel AsIrX (X = S, Se, Te) ternary chalcogenides

The high thermal stability and adjustable optoelectronic properties of ternary chalcogenide semiconductors make them distinguishable among various classes of materials. Using the standard density functional theory, we investigated the novel AsIrX (X = S, Se, Te) semiconductors' electronic structure, elastic, optical, and thermoelectric properties. The computed phonon dispersion plots confirm the thermodynamic stability of these materials. These materials possess an indirect energy gap nature. The mechanical stability is demonstrated by their positive Shear constant values. These materials are all ductile, incompressible, and elastically stable. To evaluate the possible effectiveness in optical applications, the constituents of the complex dielectric function such as absorption coefficients, real optical conductivity, energy loss functions, refractive index, reflectivity, and extinction coefficient are examined. The intense peaks in the ε1(ω) eventually drop towards the negative energy region, suggesting metallicity. The highest peaks of the absorption coefficients were noticed at 13.5 eV for these materials, suggesting these as acceptable choices for UV optoelectronic application. The materials employed probably have desirable characteristics at these temperatures because of the notable rise in ZT values.

Comparative analysis of machine learning techniques in predicting dielectric behavior of ternary chalcogenide thin films

Abstract The current research introduces a comparative analysis of the dielectric behavior exhibited by ternary chalcogenide thin films, including both experimental data and machine learning techniques. The study of temperature and frequency dependencies of dielectric parameters is crucial for assessing material losses, particularly focusing on the low-frequency range where dielectric dispersion occurs. The experimental results on the frequency (100–1000000 Hz)and the temperature(303–393 K) influences on the dielectric (constant ( ε 1 ) and loss ( ε 2 )) of A s 4 G e 24 T e 72 composition in thin film form have been discussed. Results demonstrate that ε 1 exhibits an increasing trend with temperature, attributed to heightened orientation polarization as dipoles gain mobility with elevated thermal energy. Conversely, ε 1 declines with rising frequency, reflecting diverse different polarization mechanisms. Understanding these behaviors is important for material characterization and applications in fields like electronics and solar cells. A comparative analysis of the dielectric behavior exhibited by ternary chalcogenide thin films, including both experimental data and machine learning techniques. Through the experimental approach, the dielectric properties of the films are investigated. Additionally, the study employs a range of machine learning algorithms, including Artificial Neural Networks (ANN), Adaptive Neuro-Fuzzy Inference Systems (ANFIS), Genetic Programming (GP), hybrid techniques ANFIS-GA, and ANFIS-PSO, to model and predict the dielectric behavior with remarkable accuracy. The paper presents a comparison between the performance of the proposed machine learning models, highlighting their strengths and limitations in capturing the complex dielectric phenomena observed in the ternary chalcogenide thin films. This comparative study not only provides valuable insights into the dielectric properties of these materials but also demonstrates the efficacy of machine learning in understanding and predicting their behavior, paving the way for further advancements in materials science and device development.

Bismuth-based ternary chalcogenides Pt3Bi4X9 (X = S, Se) as promising thermoelectric materials

We present a theoretical investigation of thermoelectric transport properties of bismuth-based ternary chalcogenides Pt3Bi4X9 (X = S, Se), which has low thermal conductivity and promising zT as discovered in a recent experiment [Wang et al., J. Am. Chem. Soc. 146, 7352 (2024)], using density functional theory combined with the Boltzmann transport equation within rigid band approximation. We find that the high density of states of valence bands near the Fermi level yields high p-type Seebeck coefficient. The lower effective mass of electron in Pt3Bi4S9 leads to high mobility and long relaxation time, and hence the high n-type electrical conductivity. In contrast, the effective mass of electron is much higher than that of hole in Pt3Bi4Se9 due to the flatted conduction band, which in turn gives rise to higher p-type electrical conductivity. As a result, the p-type zT is much higher than n-type in Pt3Bi4Se9, with an optimal value of 0.5 at 300 K. Considering the experimental carrier concentration for Pt3Bi4S9 (−1.4 × 1019 cm−3) and Pt3Bi4Se9 (−0.898 × 1019 cm−3), calculated n-type zT at 773 K are 0.52 and 0.04, respectively, which are consistent well with the experimental values. Our calculations uncover the upper limit thermoelectric zT of Pt3Bi4X9 and also highlight them as promising thermoelectric materials.

Pressure-induced band gap enhancement and temperature-dependent thermoelectric characterization of semiconducting Transition Metal Chalcogenides LiMS (M = Cu, Ag)

The first principles study of Transition Metal Chalcogenides LiMS (M = Cu, Ag) has been conducted utilizing the concepts of Density Functional Theory (DFT). Both the compounds possess a cubic structure with space group F-43m. The mechanical stability of LiCuS and LiAgS has been predicted based on the values of elastic tensor. These Chalcogenides possess an interesting electronic band structure which reveals their semiconducting nature with a direct band gap. The electronic structure is further subjected to high pressure and the changes in band gap are deeply observed. For these materials, the changes in band gap in response to applied pressure suggest the possibility of their use in band gap engineering. The phonon curves are investigated over the Brillouin zone's high symmetry directions which reveal the lattice dynamical stability of the presently studied compounds. Moreover, the atoms present at different positions inside a crystal lattice exhibit vibrations of different intensities and in different directions which have been studied through the Eigenvector representations. The thermoelectric properties of LiCuS and LiAgS have been characterized using Boltzmann's theory over the range of temperature between 100 K and 1600 K. The calculated thermoelectric parameters reveal the high thermoelectric efficiency of these materials with excellent values of the figure of merit. The interesting properties of ternary Chalcogenides LiMS (M = Cu, Ag) make them promising candidates for thermoelectric applications.

High thermoelectric performance induced by strong anharmonicity in ternary Li-based chalcogenides

High thermoelectric performance induced by strong anharmonicity in ternary Li-based chalcogenides

Intense Circular Dichroism and Spin Selectivity in AgBiS2 Nanocrystals by Chiral Ligand Exchange.

Chiral semiconducting nanomaterials offer many potential applications in photodetection, light emission, quantum information, and so on. However, it is difficult to achieve a strong circular dichroism (CD) signal in semiconducting nanocrystals (NCs) due to the complexity of chiral ligand surface engineering and multiple, uncertain mechanisms of chiroptical behavior. Here, a chiral ligand exchange strategy with cysteine on the ternary metal chalcogenide AgBiS2 NCs is developed, and a strong, long-lasting CD signal in the near-UV region is achieved. By carefully optimizing the ligand concentration, the CD peaks are observed at 260 and 320nm, respectively, giving insight into the different ligand binding mechanisms influencing the CD signal of AgBiS2 NCs. Using density-functional theory, a large degree of crystal distortion by the bidentate mode of ligand chelation, and efficient ligand-NC electron transfer, synergistically resulting in the strongest CD signal (g-factor over 10-2) observed in chiral ligand-exchanged semiconductor NCs to date, is demonstrated. To demonstrate the effective chiral properties of these AgBiS2 NCs, a spin-filter device with over 86% efficiency is fabricated. This work represents a considerable leap in the field of chiral semiconductor NCs and points toward their future applications.

Complex copper-based chalcogenides: a review of phase equilibria and thermodynamic properties

Complex copper-based chalcogenides are among the most important functional materials in modern engineering and technology due to their diverse physical and physicochemical properties, environmental safety and availability. The development of new similar materials and the improvement of the applied characteristics of known compounds is largely associated with the use of approaches based on the physicochemical analysis and, in particular, the “composition-structure-property” relationship. This review summarizes the available data on phase equilibria in ternary systems Cu-Tl(BIV, BV)-X (BIV-Si, Ge, Sn; BV-As, Sb, Bi; X-S, Se, Te) and the thermodynamic properties of their intermediate phases. Similar data are also considered for more complex systems forming solid solutions of various types of substitution based on known ternary copper chalcogenides. A significant part of the presented sets of mutually consistent data on phase equilibria and thermodynamic properties of the considered systems was obtained by our group over the past 10-15 years. Although these data cover only a small part of the systems described above, they provide great possibilities for manipulation of composition and structure, including entropic engineering strategies. The authors consider it extremely important to further develop fundamental research on phase equilibria and thermodynamic properties of complex copper chalcogenides and use their results widely in selecting alloy compositions for physical measurements

Fast and Sensitive Determination of Iodide Based on Ternary Chalcogenides Nanoparticles.

A fluorescent probe based on ternary AgFeS2 quantum dots has been prepared for the design of ternary chalcogenides. The nanoparticles are synthesized with oleylamine as a stabilizer at a low temperature (particle size in the range of 2 to 3 nm) and they exhibit an intense blue emission in aqueous media. As for their internal structure, each nanoparticle's relative stoichiometric ratio (AgFe1.01S1.91) is very close to the theoretical value of 1:1:2. Their magnetic properties have been studied with a vibrating sample magnetometer and they have ferromagnetism between 4 K and 298 K (applied magnetic field ranging between -10,000 and 10,000 Oe). In the presence of iodide ions, the emission at 458 nm derived from AgFeS2 QDs has been observed to give rise to fluorescence quenching. The detection system is based on a static quenching process and morphological change between iodide ions and AgFeS2, which has a good linear range from 0 to 37.5 μmol/L, with a limit of detection of 0.99 μM. The nanoprobe responds within 30 s for the efficient detection of iodide. Such functional quantum dots will provide a powerful indicator in environmental and bio-sensing applications.

Cobalt Molybdenum Telluride as an Efficient Trifunctional Electrocatalyst for Seawater Splitting

A mixed-metal ternary chalcogenide, cobalt molybdenum telluride (CMT), has been identified as an efficient tri-functional electrocatalyst for seawater splitting, leading to enhanced oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR). The CMT was synthesized by a single step hydrothermal technique. Detailed electrochemical studies of the CMT-modified electrodes showed that CMT has a promising performance for OER in the simulated seawater solutions, exhibiting a small overpotential of 385 mV at 20 mA cm−2, and superior catalyst durability for prolonged period of continuous oxygen evolution. Interestingly, while gas chromatography analysis confirmed the evolution of oxygen in an anodic chamber, it showed that there was no chlorine evolution from these electrodes in alkaline seawater, highlighting the novelty of this catalyst. CMT also displayed remarkable ORR activity in simulated seawater as indicated by its four-electron reduction pathway forming water as the dominant product. One of the primary challenges of seawater splitting is chlorine evolution from the oxidation of dissolved chloride salts. The CMT catalyst successfully and significantly lowers the water oxidation potential, thereby separating the chloride and water oxidation potentials by a larger margin. These results suggest that CMT can function as a highly active tri-functional electrocatalyst with significant stability, making it suitable for clean energy generation and environmental applications using seawater.

Achieving Tunable Band Structure and Photocarrier Dynamics by Regulating 2D Atomic Layer Stacking Toward High‐Performance Self‐Powered Broadband and Deep‐UV Photodetection

Abstract2D materials with unique layer‐dependent electronic structure can bring precise control to their photocarrier dynamics for optimizing and expanding optoelectronic applications, while the challenge of controlling layer stacking makes the layer dependency law still underexplored in emerging 2D ternary metal chalcogenides. Herein, 2D rhombohedral‐phase ZnIn2S4 (R‐ZIS) with controllable layer thickness is achieved by confined‐growth strategy in high yield, exhibiting continuously tunable direct bandgap (2.39–2.77 eV) with evident upshift of conduction band minimum (CBM) and Fermi level (EF), demonstrated arising from the synergistic effect of reduced interlayer interaction with inevitably increasing Zn defects. Remarkably, the carrier dynamics of R‐ZIS in photoelectrochemical (PEC) device is successfully regulated by adjusted CBM and EF, resulting in continuously tunable optical absorption band, photocarrier separation efficiency, self‐powered capability, and dark current noise. Beneficial from tailored band structure and carrier dynamics, self‐powered PEC‐type photodetector with broadband photoresponse (254–765 nm), is achieved fast response speed (12.3/5.3 ms) and high responsivity (90.29 mA W−1) in multilayer R‐ZIS, while deep‐UV photodetector with ultra‐high specific detectivity (1.62 × 1012 Jones) at 254 nm in monolayer R‐ZIS, exhibiting the record performance in both fields. This work motivates the development of tailored band structure for 2D‐materials‐based optoelectronic devices in strategy and mechanism.

Advanced Computational Insights Into the Optical, Electronic, and Thermoelectric Characteristics of Novel Rare‐Earth Ternary Chalcogenides

ABSTRACTRare‐earth ternary materials are distinguished by their tunable optoelectronic characteristics and high thermal stability. First principles computations examine the intricate interaction of novel rare‐earth‐based ternary chalcogenide's electronic, optical, and thermoelectric properties. The spin‐down channel of PrHSe exhibits a substantial energy gap resulting in half‐metallic behavior. The f orbitals of Pr and Er play an important role in forming bonds with Se and H atoms, contributing significantly to the valence band. The preponderance of Pr‐f and Er‐f orbitals near the top of the valence band indicate that electrons in these orbitals are the most energetic and participate in bonding interactions within these materials. The ErHSe has a greater absorption rate than PrHSe, and both materials behave isotropically in the xx and zz directions. The highest peaks of the reflection coefficient (50%–70%) in the 1.0–13.8 eV range suggested a significant level of UV reflectivity. The PrHSe has a higher intrinsic carrier concentration for conduction than ErHSe. At lower temperatures, carrier concentrations increase due to thermal activation processes, improving the Seebeck coefficient in these materials.

Computational insights into structural, electronic, optical and thermoelectric features of ternary chalcogenide Ca2GeX4 (X=S, Se, Te) compounds

The advancements in materials engineering for clean energy and greenhouse gas reduction has attracted global attention. Furthermore, the distinct electrical and optical properties of ternary chalcogenides are critical for their application in solar energy conversion. In this study, the electronic, optical, thermodynamic, and thermoelectric transport properties of the ternary chalcogenide Ca2GeX4 (X = S, Se, and Te) compounds are comprehensively investigated using the density functional theory-based WIEN2k package. The findings indicate that ternary chalcogenide Ca2GeX4 compounds possess substantial band gaps and display strong covalent bonding characteristics. Analysis of the density of states reveals minimal impact from S-s and S-p states, while highlighting the significance of Ca-s and Ge-s states. The investigated materials show significant UV absorption with reflectance between 30 and 40 % which peaks at 13.5 eV at about 65 %, confirming the optical properties of the ternary chalcogenide Ca2GeX4. The positive Seebeck coefficient suggests that holes are the primary charge carriers in tested materials, with thermal energy rising in accordance with the chalcogenide's atomic number. Several thermoelectric properties that demonstrate the suitability of these materials for thermoelectric applications were also discussed. Overall, the findings confirm the thermoelectric and optoelectronic properties of Ca2GeX4 materials, which may facilitate the creation and development of effective optoelectronic devices.

First-Principles Study of the Mechanical, Electronic, and Optical Properties of Ternary Chalcogenide Compounds

First-Principles Study of the Mechanical, Electronic, and Optical Properties of Ternary Chalcogenide Compounds

Exploring novel Zn2SeX (X=S, Te) ternary chalcogenide: Studying the effect of chalcogen substitution on optoelectronic, and thermoelectric performance

Ternary-type semiconductor chalcogenide materials are distinguished by their outstanding thermal performance and tunable optoelectronic features. The electronic structure, optical, and transport features of novel Zn2SeX ternary (X=S, Te) semiconductors are investigated by employing the widely used density functional theory. Based on the band structure investigation, these materials were anticipated tohave a direct energy gap. The results demonstrated that direct energy losses were caused by the orbitals hybridization of S-p and the Se/Te-d in both materials. Compared to Zn2SeTe, Zn2SeS has a wider band gap at the Γ-point, meaning that electrons will have a lower effective mass and atoms possess a greater effective mass. The elements of the complex dielectric function and the significant optical properties were explored for potential use in optoelectronic applications. The unique peaks in I(ω) confirm extensive absorption in the UV range. They may be employed as very effective ultraviolet-reflecting materials based on the peaks in the reflection spectrum that have been observed. Since both materials positive Seebeck coefficient display p-type conductivity over the whole temperature range.

EXPLORING THE STRUCTURAL AND ELECTRONIC CHARACTERISTICS OF AMORPHOUS Ge – Te - In MATERIAL THROUGH AB INITIO METHODS

This study employs density functional theory (DFT) and molecular dynamics to meticulously investigate the structural and electronic properties of ternary chalcogenide compounds, specifically (GeTe4 ) 1-x Inx, and (GeTe5 )1-x Inx across a range of compositions ( x = 0, 5, 10, 15, 20 at %). Utilizing the local density approximation within the framework of first-principles calculations, we comprehensively analyze the pair correlation function, static structural factor, electronic density of states, and electronic band gap energy. Our results reveal a notable decrease in the energy band gap of Germanium-Tellurium with the incorporation of Indium atoms. The structural changes observed in the Ge-Te matrix with Indium doping, as evidenced by the changes in the pair correlation function and static structure factor, are consistent with and supportive of the observed decrease in the band gap energy. This phenomenon is primarilyattributed to the significant contribution of Indium atoms to the conduction band edge, offering new insights into the material’s electronic behaviour.

Investigating novel Mo2X3S (X = Se, Te) materials: probing the influence of chalcogen substitution on electronic, optical, and thermoelectric properties

The excellent thermal performance and adjustable optoelectronic characteristics distinguish the ternary semiconductors. Using the state-of-the-art density functional theory, the optoelectronic, and thermoelectric characteristics of new Mo2X3S (X = Se, Te) ternary chalcogenides are studied. The predicted band gap values with TB-mBJ for Mo2Se3S and Mo2Te3S materials were 1.41 eV and 2.10 eV, respectively. For their possible employment in optoelectronic applications, the components of the complex dielectric function and the vital optical characteristics were calculated and studied. For an increase in the band gap and with the replacement of Se to Te, the peaks in ε 1(ω) shifted to higher energies. Mo2Se3S and Mo2Te3S both show stronger absorption in the UV and visible ranges. Based on the observed peaks in the reflection spectrum, they may used as ultraviolet-reflecting materials with good efficacy. Both Mo2Se3S and Mo2Te3S have positive Seebeck coefficient values, they exhibit p-type conduction. The Mo2Te3S material displays a maximum Seebeck coefficient at about 500 K compared to Mo2Se3S, which leads to a maximum ZT.