Ternary Metal Chalcogenide Research Articles

FeIn2S4 Nanocrystals: A Ternary Metal Chalcogenide Material for Ambipolar Field-Effect Transistors.

An ambipolar channel layer material is required to realize the potential benefits of ambipolar complementary metal–oxide–semiconductor field‐effect transistors, namely their compact and efficient nature, reduced reverse power dissipation, and possible applicability to highly integrated circuits. Here, a ternary metal chalcogenide nanocrystal material, FeIn2S4, is introduced as a solution‐processable ambipolar channel material for field‐effect transistors (FETs). The highest occupied molecular orbital and the lowest unoccupied molecular orbital of the FeIn2S4 nanocrystals are determined to be −5.2 and −3.75 eV, respectively, based upon cyclic voltammetry, X‐ray photoelectron spectroscopy, and diffraction reflectance spectroscopy analyses. An ambipolar FeIn2S4 FET is successfully fabricated with Au electrodes (E F = −5.1 eV), showing both electron mobility (14.96 cm2 V−1 s−1) and hole mobility (9.15 cm2 V−1 s−1) in a single channel layer, with an on/off current ratio of 105. This suggests that FeIn2S4 nanocrystals may be a promising alternative semiconducting material for next‐generation integrated circuit development.

Chemical strain formation through anion substitution in Cu2WS4 for efficient electrocatalysis of water dissociation

The electrocatalytic activity of ternary metal chalcogenides is improved by anion substitution that creates a chemical strain in the lattice.

Growth Mechanism and Surface State of CuInS2 Nanocrystals Synthesized with Dodecanethiol.

Ternary metal chalcogenide nanocrystals (NCs) offer exciting opportunities as novel materials to be explored on the nanoscale showing optoelectronic properties tunable with size and composition. CuInS2 (CIS) NCs are the most widely studied representatives of this family as they can be easily prepared with good size control and in high yield by reacting the metal precursors (copper iodide and indium acetate) in dodecanethiol (DDT). Despite the widespread use of this synthesis method, both the reaction mechanism and the surface state of the obtained NCs remain elusive. Here, we perform in situ X-ray diffraction using synchrotron radiation to monitor the pre- and postnucleation stages of the formation of CIS NCs. SAXS measurements show that the reaction intermediate formed at 100 °C presents a periodic lamellar structure with a characteristic spacing of 34.9 Å. WAXS measurements performed after nucleation of the CIS NCs at 230 °C demonstrate that their growth kinetics depend on the degree of precursor conversion achieved in the initial stage at 100 °C. NC formation requires the cleavage of S-C bonds. We reveal by means of combined 1D and 2D proton and carbon NMR analyses that the generated dodecyl radicals lead to the formation of a new thioether species R-S-R. The latter is part of a ligand double layer, which consists of dynamically bound dodecanethiolate ligands as well as of head-to-tail bound R-S-R molecules. This ligand double layer and a high ligand density (3.6 DDT molecules per nm2) are at the origin of the apparent difficulty to functionalize the surface of CIS NCs obtained with the DDT method.

Ultrathin Two-Dimensional Multinary Layered Metal Chalcogenide Nanomaterials.

Ultrathin two-dimensional (2D) layered transition metal dichalcogenides (TMDs), such as MoS2 , WS2 , TiS2 , TaS2 , ReS2 , MoSe2 and WSe2 , have attracted considerable attention over the past six years owing to their unique properties and great potential in a wide range of applications. Aiming to achieve tunable properties and optimal application performances, great effort is devoted to the exploration of 2D multinary layered metal chalcogenide nanomaterials, which include ternary metal chalcogenides with well-defined crystal structures, alloyed TMDs, heteroatom-doped TMDs and 2D metal chalcogenide heteronanostructures. These novel 2D multinary layered metal chalcogenide nanomaterials exhibit some unique properties compared to 2D binary TMD counterparts, thus holding great promise in various potential applications including electronics/optoelectronics, catalysis, sensors, biomedicine, and energy storage and conversion with enhanced performances. This article focuses on the state-of-art progress on the preparation, characterization and applications of ultrathin 2D multinary layered metal chalcogenide nanomaterials.

Ternary Transitional Metal Chalcogenide Nanosheet with Significantly Enhanced Electrocatalytic Hydrogen-Evolution Activity

Electrochemical production of hydrogen from water holding tremendous promise for clean energy has been directed to the search for non-noble metal based and earth-abundant catalysts. Here we report dramatically enhanced HER catalysis of ternary I-Cu2WS4 nanosheets from chemically exfoliated via lithium intercalation. Structural characterization and electrochemical study confirmed that the enhanced electrocatalytic activity of I-Cu2WS4 nanosheets is associated with the larger surface area to provide an easy path for the hopping of electrons. This study opens a new way for the development of ternary highly active non-noble electrocatalysts for hydrogen production from water splitting.

General method of synthesis ultrathin ternary metal chalcogenide nanowires for potential thermoelectric applications

In this work we demonstrate a solution-based approach to the synthesis of ternary metal chalcogenide nanowires (NWs) with high thermoelectric figure of merit (ZT) and power factors. Utilizing templates of Te1−xSex alloys to balance the chemical reactivity between Te and Se atoms, we have been able to add a number of different metal species while maintaining a single-phase ternary metal chalcogenide NW with small diameter (<20 nm) and well defined crystal structure. This method opens the door for scalable synthesis ultrathin and composition tunable selenium doped ternary chalcogenide NWs. Moreover, spark plasma sintered NW-based bulk material exhibits ZT value as high as 0.75 which excessed previously nanocrystal and nanoplatelet based one. Examining the temperature dependent behavior of conductivity and Seebeck coefficient, we suggest the charge transfer mechanisms within the system are dominated by the energy barrier between NW-NW nano-junctions.

Ag3SbS3 thin films formed by annealing hydrothermally synthesized Ag3SbS3 nanoparticles

We report the growth of thin films of ternary metal chalcogenide Ag3SbS3. The growth involves two steps: (1) Ag3SbS3 nanoparticles were synthesized using the hydrothermal method; (2) a post-annealing process transformed the Ag3SbS3 nanoparticles into Ag3SbS3 films. The best Ag3SbS3 nanoparticles were obtained with the hydrothermal reaction temperature of 140°C for 12h. The formation of Ag3SbS3 films is sensitive to the annealing temperature and the best films were produced at 440°C. The XRD pattern reveals the Ag3SbS3 single phase. The prepared Ag3SbS3 film has a smooth, uniform surface with a medium particle size of ~200nm. Optical absorption reveals an energy gap of 1.8eV and a large absorption coefficient of 2.1×105cm−1 at λ=400nm. The large optical absorption suggests that Ag3SbS3 films could be a potential solar cell material. Compared to the laser technique used formally, the present growth method is simpler, lower cost and able to produce high-quality Ag3SbS3 films.

Ba2In2Q5 (Q = S, Se): Synthesis, Crystal Structures, Electronic Structures, and Optical Properties

AbstractTwo ternary metal chalcogenides, Ba2In2Q5 (Q = S, Se) were successfully synthesized by solid‐state reactions. They are isostructural and crystallize in the orthorhombic space group Pbca (no. 61). Both of them have a similar three‐dimensional (3D) framework structure, which is composed of [InQ4] (Q = S, Se) tetrahedra that are alternatingly connected on layer in the ab plane, with Ba2+ cations arranged between In–S or In–Se layers for electric charge balance. The measured Raman and IR spectra show that title compounds have broad transparency range up to 20 μm. From the UV/Vis/NIR diffuse reflectance spectra, it can be seen that the bandgaps of Ba2In2S5 and Ba2In2S5 are 2.47 eV and 2.12 eV, which are larger than these of the calculation values (Ba2In2S5, 2.362 eV and Ba2In2Se5, 1.908 eV), respectively. The calculated partial densities of states indicate that the bandgaps are determined by the interaction of S‐3p and In‐5s (Ba2In2S5) or Se‐4p and In‐5s (Ba2In2Se5), respectively. The calculated birefringences (Δn) are about 0.03 (Ba2In2S5) and 0.05 (Ba2In2Se5) as the wavelength above 1 μm, respectively.

Electronic, optical properties, surface energies and work functions of Ag8SnS6: First-principles method**Project supported by the Science and Technology Development Foundation of China (Grant Nos. 2012A0302015 and 2012B0302050).

Ternary metal chalcogenide semiconductor Ag8SnS6, which is an efficient photocatalyst under visible light radiation, is studied by plane-wave pseudopotential density functional theory. After geometry optimization, the electronic and optical properties are studied. A scissor operator value of 0.81 eV is introduced to overcome the underestimation of the calculation band gaps. The contribution of different bands is analyzed by virtue of total and partial density of states. Furthermore, in order to understand the optical properties of Ag8SnS6, the dielectric function, absorption coefficient, and refractive index are also performed in the energy range from 0 to 11 eV. The absorption spectrum indicates that Ag8SnS6 has a good absorbency in visible light area. Surface energies and work functions of , , , and (112) orientations have been calculated. These results reveal the reason for an outstanding photocatalytic activity of Ag8SnS6.

Biomolecule-assisted synthesis of ZnIn2S4 flower-like hollow microspheres

The ternary metal chalcogenide ZnIn2S4 flower-like hollow microsphere was synthesized by a solvothermal reaction of Zn(CH3COO)2·2H2O, InCl3·4H2O and l-cysteine in ethylene glycol at 160°C for 24h. The crystal structure was characterized by X-ray diffractometry. Field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses show that the products consist of hollow microspheres made up of nanosheets and the thickness of the nanosheets is found to be less than 10nm. A possible mechanism for the formation of the flower-like hollow microspheres is also proposed in this paper.

CuInS2-Sensitized Quantum Dot Solar Cell. Electrophoretic Deposition, Excited-State Dynamics, and Photovoltaic Performance.

Ternary metal chalcogenides such as CuInS2 offer new opportunities to design quantum dot solar cells (QDSC). Chemically synthesized CuInS2 quantum dots (particle diameter, 2.6 nm) have been successfully deposited within the mesoscopic TiO2 film using electrophoretic deposition (150 V cm(-1) dc field). The primary photoinduced process of electron injection from excited CuInS2 into TiO2 occurs with a rate constant of 5.75 × 10(11) s(-1). The TiO2/CuInS2 films are photoactive and produce anodic photocurrent with a power conversion efficiency of 1.14%. Capping the TiO2/CuInS2 film with a CdS layer decreases the interfacial charge recombination and thus offers further improvement in the power conversion efficiency (3.91%). The synergy of using CdS as a passivation layer in the composite film is also evident from the increased external quantum efficiency of the electrode in the red region where only CuInS2 absorbs the incident light.

Ternary and quaternary metal chalcogenide nanocrystals: synthesis, properties and applications

We review the field of multinary metal chalcogenide nanocrystals, which has gained strongly increasing interest in the quest for novel narrow band gap semiconductors. Small (2–4 nm) CuInS2 and CuInSe2 nanocrystals, for example, exhibit size dependent luminescence in the visible and near infrared range. Their quantum yield can exceed 50% after growth of a ZnS shell, which makes them appealing emitters for lighting, displaying and biological imaging applications. Cu2ZnSnS4 (CZTS) nanocrystals, on the other hand, can be used as solution processed absorbing materials in thin film solar cells showing high power conversion efficiencies (currently around 8–10%). These examples illustrate that multinary metal chalcogenide nanocrystals have high potential for replacing classical cadmium and lead chalcogenide quantum dots in many fields. We give an overview of the chemical synthesis methods of the different systems reported to date, classifying them according to the obtained crystal structure. Next, we discuss their photophysical properties and give a brief description of the main fields of application. Finally, we conclude by outlining current challenges and related future directions of this exponentially growing domain.

Ionothermal/hydrothermal synthesis of the ternary metal chalcogenide ZnIn 2S 4

The ternary metal chalcogenide ZnIn 2S 4 was synthesized through the ionothermal/hydrothermal method using the ionic liquid [Bmim][BF 4]. The crystal structure and surface chemical state of the product were confirmed by X-ray diffractometry and X-ray photoelectron spectroscopy. A small amount of water was essential for the obtaining of yellow ZnIn 2S 4 product. ZnIn 2S 4 with a hexagonal phase was obtained in a wide range of [Bmim][BF 4]:water ratios of 9.3 ml:(0.1–5 ml). The size and morphology of the synthesized samples were strongly affected by the aid of [Bmim][BF 4], the amount of water, the zinc source, reaction temperature, and reaction time. The ZnIn 2S 4 showed different visible light absorption ranges when the water content of the reaction mixture was varied.

A general microwave-assisted nonaqueous approach to nanocrystalline ternary metal chalcogenide and the photoluminescence study of CoIn 2S 4

A new synthetic approach to nanocrystalline ternary metal chalcogenides (CoIn 2S 4, CuInS 2, AgInS 2, and CuFeS 2) was developed by taking advantage of microwave irradiation and nonaqueous route in mixed amine (octadecylamine or benzylamine) and benzyl alcohol. The resulting products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), UV–vis diffuse reflectance spectroscopy, and photoluminescence (PL). The PL analysis first indicated the unique photoluminescence property of the resulting CoIn 2S 4 nanocrystals and suggested its potential applications in optical devices. We found the crucial and different roles of octadecylamine and benzylamine playing for the formation of various ternary metal chalcogenides. More importantly, this study demonstrates a simple, energy efficient and time-saving approach that may be extended to prepare other promising ternary metal chalcogenide nanocrystals.

Ternary non-noble metal chalcogenide (W–Co–Se) as electrocatalyst for oxygen reduction reaction

In this study, a catalyst based on a novel ternary non-noble metal chalcogenide, W–Co–Se, was synthesized for the oxygen reduction reaction (ORR) in acidic medium. The non-noble metal chalcogenide catalyst was electrochemically stable in the potential range of 0.05–0.8 V versus NHE in 0.5 M H 2SO 4 aqueous solution. This catalyst demonstrated significant catalytic activity towards the ORR, showing the ORR onset potential at 0.755 V versus NHE in 0.5 M H 2SO 4 at 25 °C. Such high activity might be attributed to the electronic structure of non-noble metals modified by chalcogen.

Phase diagrams of degenerate states in ternary metal and metal chalcogenide systems with solid solutions

Models with a good-fit have been developed for the phase diagrams of ternary systems with intermediate solid phases of variable and fixed compositions, including diagrams with limited or degenerate solid solutions in subsystems.

Some complexes of neopentylcadmium species with dithio-and di-selenocarbamates: The synthesis, characterization and single crystal X-ray structure of a mixed neopentyl/diethyldiselenocarbamate of cadmium: [(CH 3) 3CCH 2CdSe 2CNEt 2] 2

The synthesis and characterization of the neopentyl complexes of cadmium (CH 3) 3CH 2CCdE 2CNEt 2 (E  S or Se) and the related mixed metal species (CH 3) 3CH 2CZn 0.5Cd 0.5Se 2CNEt 2 are reported. A single crystal X-ray structure determination on for (CH 3) 3CH 2CCdSe 2CNEt 2; the compound is dimeric. All of the complexes decompose to give the corresponding binary or ternary metal chalcogenides.

Framework structures in metal chalcogenides and the characterization of their bonding by magnetic properties

Abstract Framework structures of ternary metal chalcogenides with tetrahedral and planar coordination of transition metal atoms are discussed by using an extended Zintl principle. Their bonding can be characterized by the magnetic moments measured by neutron diffraction. The experimental results are compared with crystal field splittings obtained by calculations based on the strong field model. This is an attempt to explain the occurrence of reduced spin states of transition metal atoms in tetrahedral coordination in terms of a dependence on the framework structure.