Ligand-Assisted Colloidal Synthesis of Alkali Metal-Based Ternary Chalcogenide: Nanostructuring and Phase Control in Na-Cu-S System.

The development of sustainable and tunable materials is crucial for advancing modern technologies. We present a controlled synthesis of colloidal Na-Cu-S nanostructures. To overcome the reactivity difference between Na and Cu precursors toward chalcogens in a colloidal synthesis and to achieve metastable phase formation, we designed a single-source precursor for Cu and S.

Structural and electronic features enabling delocalized charge-carriers in CuSbSe.

Inorganic semiconductors based on heavy pnictogen cations (Sb and Bi) have gained significant attention as potential nontoxic and stable alternatives to lead-halide perovskites for solar cell applications. A limitation of these novel materials, which is being increasingly commonly found, is carrier localization, which substantially reduces mobilities and diffusion lengths. Herein, CuSbSe is investigated and discovered to have delocalized free carriers, as shown through optical pump terahertz probe spectroscopy and temperature-dependent mobility measurements.

Transport Properties of Doped Wide Band Gap Layered Oxychalcogenide Semiconductors SrGaOCu, SrScOCu, and SrInOCu ( = S or Se).

The structural, electrical, and optical properties of a series of six layered oxychalcogenides with the general formula Sr OCu, where M = Ga, Sc, or In and = S or Se, have been investigated. From this set, we report the structure and properties of SrGaOCuSe for the first time, as well as the full structural details of SrScOCuSe, which have not previously been available. A systematic study of the suitability of all of the Sr OCu phases as -type conductors has been carried out, after doping with both sodium and potassium to a nominal composition of Sr OCu, ( = Na or K), to increase the hole carrier concentration.

Observation and enhancement through alkali metal doping of p-type conductivity in the layered oxyselenides SrZnOCuSe and BaZn O CuSe.

The optoelectronic properties of two layered copper oxyselenide compounds, with nominal composition SrZnOCuSe and BaZnOCuSe, have been investigated to determine their suitability as p-type conductors. The structure, band gaps and electrical conductivity of pristine and alkali-metal-doped samples have been determined. We find that the strontium-containing compound, SrZnOCuSe, adopts the expected tetragonal structure with 4/ symmetry, and has a band gap of 2.

Band Degeneracy and Anisotropy Enhances Thermoelectric Performance from SbSiTe to ScSiTe.

The complex interrelationships among thermoelectric parameters mean that design of high-performing materials is difficult. However, band engineering can allow the power factor to be optimized through enhancement of the Seebeck coefficient. Herein, using layered SbSiTe and ScSiTe as model systems, we comprehensively investigate and compare their thermoelectric properties by employing density functional theory combined with semiclassical Boltzmann transport theory.

Li-Site Defects Induce Formation of Li-Rich Impurity Phases: Implications for Charge Distribution and Performance of LiNi MMnO Cathodes (M = Fe and Mg; x = 0.05-0.2).

An understanding of the structural properties that allow for optimal cathode performance, and their origin, is necessary for devising advanced cathode design strategies and accelerating the commercialization of next-generation cathodes. High-voltage, Fe- and Mg-substituted LiNiMnO cathodes offer a low-cost, cobalt-free, yet energy-dense alternative to commercial cathodes. In this work, the effect of substitution on several important structure properties is explored, including Ni/Mn ordering, charge distribution, and extrinsic defects.

Computational Prediction of an Antimony-Based n-Type Transparent Conducting Oxide: F-Doped SbO.

Transparent conducting oxides (TCOs) possess a unique combination of optical transparency and electrical conductivity, making them indispensable in optoelectronic applications. However, their heavy dependence on a small number of established materials limits the range of devices that they can support. The discovery and development of additional wide bandgap oxides that can be doped to exhibit metallic-like conductivity are therefore necessary.

Controlling the Superconductivity of NbPdS via Reversible Li Intercalation.

The NbPdS ( ≈ 0.74) superconductor with a of 6.5 K is reduced by the intercalation of lithium in ammonia solution or electrochemically to produce an intercalated phase with expanded lattice parameters.

Exploring Bismuth Coordination Complexes as Visible-Light Absorbers: Synthesis, Characterization, and Photophysical Properties.

Bismuth-based coordination complexes are advantageous over other metal complexes, as bismuth is the heaviest nontoxic element with high spin-orbit coupling and potential optoelectronics applications. Herein, four bismuth halide-based coordination complexes [BiCl(phen-thio)] (), [BiBr(phen-thio)] (), [BiI(phen-thio)] (), and [BiI(phen-Me)] () were synthesized, characterized, and subjected to detailed photophysical studies. The complexes were characterized by single-crystal X-ray diffraction, powder X-ray diffraction, and NMR studies.

Correction: Investigation of factors affecting the stability of compounds formed by isovalent substitution in layered oxychalcogenides, leading to identification of BaScOCuSe, BaYOCuSe, BaScOAgSe and BaInOAgSe.

[This corrects the article DOI: 10.1039/D1TC05051F.].

Limits to Hole Mobility and Doping in Copper Iodide.

Over one hundred years have passed since the discovery of the p-type transparent conducting material copper iodide, predating the concept of the "electron-hole" itself. Supercentenarian status notwithstanding, little is understood about the charge transport mechanisms in CuI. Herein, a variety of modeling techniques are used to investigate the charge transport properties of CuI, and limitations to the hole mobility over experimentally achievable carrier concentrations are discussed.

Understanding the electronic structure of YTiOS for green hydrogen production: a hybrid-DFT and GW study.

Utilising photocatalytic water splitting to produce green hydrogen is the key to reducing the carbon footprint of this crucial chemical feedstock. In this study, density functional theory (DFT) is employed to gain insights into the photocatalytic performance of an up-and-coming photocatalyst YTiOS from first principles. Eleven non-polar clean surfaces are evaluated at the generalised gradient approximation level to obtain a plate-like Wulff shape that agrees well with the experimental data.

Controlling the thermoelectric properties of organo-metallic coordination polymers through backbone geometry.

Poly(nickel-benzene-1,2,4,5-tetrakis(thiolate)) (Ni-btt), an organometallic coordination polymer (OMCP) characterized by the coordination between benzene-1,2,4,5-tetrakis(thiolate) (btt) and Ni ions, has been recognized as a promising p-type thermoelectric material. In this study, we employed a constitutional isomer based on benzene-1,2,3,4-tetrakis(thiolate) (ibtt) to generate the corresponding isomeric polymer, poly(nickel-benzene-1,2,3,4-tetrakis(thiolate)) (Ni-ibtt). Comparative analysis of Ni-ibtt and Ni-btt reveals several common infrared (IR) and Raman features attributed to their similar square-planar nickel-sulfur (Ni-S) coordination.

Accessible chemical space for metal nitride perovskites.

Building on the extensive exploration of metal oxide and metal halide perovskites, metal nitride perovskites represent a largely unexplored class of materials. We report a multi-tier computational screening of this chemical space. From a pool of 3660 ABN compositions covering I-VIII, II-VII, III-VI and IV-V oxidation state combinations, 279 are predicted to be chemically feasible.

Phase Quantification of Heterogeneous Surfaces Using DFT-Simulated Valence Band Photoemission Spectra.

Quantifying the crystallographic phases present at a surface is an important challenge in fields such as functional materials and surface science. X-ray photoelectron spectroscopy (XPS) is routinely employed in surface characterization to identify and quantify chemical species through core line analysis. Valence band (VB) spectra contain characteristic but complex features that provide information on the electronic density of states (DoS) and thus can be understood theoretically using density functional theory (DFT).

Emergent and robust ferromagnetic-insulating state in highly strained ferroelastic LaCoO thin films.

Transition metal oxides are promising candidates for the next generation of spintronic devices due to their fascinating properties that can be effectively engineered by strain, defects, and microstructure. An excellent example can be found in ferroelastic LaCoO with paramagnetism in bulk. In contrast, unexpected ferromagnetism is observed in tensile-strained LaCoO films, however, its origin remains controversial.

Interplay of Static and Dynamic Disorder in the Mixed-Metal Chalcohalide SnSbSI.

Chalcohalide mixed-anion crystals have seen a rise in interest as "perovskite-inspired materials" with the goal of combining the ambient stability of metal chalcogenides with the exceptional optoelectronic performance of metal halides. SnSbSI is a promising candidate, having achieved a photovoltaic power conversion efficiency above 4%. However, there is uncertainty over the crystal structure and physical properties of this crystal family.

Intrinsic Defects and Their Role in the Phase Transition of Na-Ion Anode NaTiO.

The development of high-power anode materials for Na-ion batteries is one of the primary obstacles due to the growing demands for their use in the smart grid. Despite the appealingly low cost and non-toxicity, NaTiO suffers from low electrical conductivity and poor structural stability, which restricts its use in high-power applications. Viable approaches for overcoming these drawbacks reported to date are aliovalent doping and hydrogenation/hydrothermal treatments, both of which are closely intertwined with native defects.

Band Alignments, Electronic Structure, and Core-Level Spectra of Bulk Molybdenum Dichalcogenides (MoS, MoSe, and MoTe).

A comprehensive study of bulk molybdenum dichalcogenides is presented with the use of soft and hard X-ray photoelectron (SXPS and HAXPES) spectroscopy combined with hybrid density functional theory (DFT). The main core levels of MoS, MoSe, and MoTe are explored. Laboratory-based X-ray photoelectron spectroscopy (XPS) is used to determine the ionization potential (IP) values of the MoX series as 5.

Frenkel Excitons in Vacancy-Ordered Titanium Halide Perovskites (CsTiX).

Low-cost, nontoxic, and earth-abundant photovoltaic materials are long-sought targets in the solar cell research community. Perovskite-inspired materials have emerged as promising candidates for this goal, with researchers employing materials design strategies including structural, dimensional, and compositional transformations to avoid the use of rare and toxic elemental constituents, while attempting to maintain high optoelectronic performance. These strategies have recently been invoked to propose Ti-based vacancy-ordered halide perovskites (ATiX; A = CHNH, Cs, Rb, or K; X = I, Br, or Cl) for photovoltaic operation, following the initial promise of CsSnX compounds.

Computational Prediction and Experimental Realization of Earth-Abundant Transparent Conducting Oxide Ga-Doped ZnSbO.

Transparent conducting oxides have become ubiquitous in modern optoelectronics. However, the number of oxides that are transparent to visible light and have the metallic-like conductivity necessary for applications is limited to a handful of systems that have been known for the past 40 years. In this work, we use hybrid density functional theory and defect chemistry analysis to demonstrate that tri-rutile zinc antimonate, ZnSbO, is an ideal transparent conducting oxide and to identify gallium as the optimal dopant to yield high conductivity and transparency.

Investigation of factors affecting the stability of compounds formed by isovalent substitution in layered oxychalcogenides, leading to identification of BaScOCuSe, BaYOCuS, BaScOAgSe and BaInOAgSe.

Four novel compositions containing chalcogenide layers, adopting the BaMOM'Ch layered structure have been identified: BaScOCuSe, BaYOCuS, BaScOAgSe and BaInOAgSe. A comprehensive comparison of experimental and computational results providing the crystallographic and electronic structure of the compounds under investigation has been conducted. Materials were synthesised at 800 °C under vacuum using a conventional ceramic synthesis route with combination of binary oxide and chalcogenide precursors.