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.

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.].

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.

Computationally Driven Discovery of Layered Quinary Oxychalcogenides: Potential -Type Transparent Conductors?

-type transparent conductors (TCs) are key materials in the modern optoelectronics industry. Despite years of research, the development of a high-performance -type TC has lagged far behind that of its -type counterparts, delaying the advent of "transparent electronics"-based p-n junctions. Here, we propose the layered oxysulfide [CuS][SrScO] as a structural motif for discovering -type TCs.

Demonstration of Visible Light-Activated Photocatalytic Self-Cleaning by Thin Films of Perovskite Tantalum and Niobium Oxynitrides.

Metal oxynitrides adopting the perovskite structure have been shown to be visible light-activated photocatalysts, and therefore, they have potential as self-cleaning materials where surface organic pollutants can be removed by photomineralization. In this work, we establish a route for the deposition of thin films for seven perovskite oxynitrides, CaTaON, SrTaON, BaTaON, LaTaON, EuTaON, SrNbON, and LaNbON, on quartz and alumina substrates using dip-coating of a polymer gel to form an amorphous oxide precursor film, followed by ammonolysis. The initially deposited oxide films were annealed at 800 °C, followed by ammonolysis at temperatures from 850 to 1000 °C.

Observation of visible light activated photocatalytic degradation of stearic acid on thin films of tantalum oxynitride synthesized by aerosol assisted chemical vapour deposition.

UV activated photocatalysts deposited using chemical vapour deposition have found commercial success as self-cleaning coatings. However, only limited work has been conducted on the use of the more recently discovered visible light activated photocatalysis for this application. Tantalum oxynitride is an established visible light photocatalyst, and in this paper we have investigated the ability of thin films of tantalum oxynitride to photocatalytically degrade a model organic pollutant, stearic acid, and therefore assess the coatings potential for self-cleaning applications.

Phosphinecarboxamide as an unexpected phosphorus precursor in the chemical vapour deposition of zinc phosphide thin films.

This paper demonstrates the use of phosphinecarboxamide as a facile phosphorus precursor, which can be used alongside zinc acetate for the chemical vapour deposition (CVD) of adherent and crystalline zinc phosphide films. Thin films of Zn3P2 have a number of potential applications and phosphinecarboxamide is a safer and more efficient precursor than the highly toxic, corrosive and flammable phosphine used in previous CVD syntheses.

Combining single source chemical vapour deposition precursors to explore the phase space of titanium oxynitride thin films.

In this paper we report on a novel chemical vapour deposition approach to the formation and control of composition of mixed anion materials, as applied to titanium oxynitride thin films. The method used is the aerosol assisted chemical vapour deposition (AACVD) of a mixture of single source precursors. To explore the titanium-oxygen-nitrogen system the single source precursors selected were tetrakis(dimethylamido) titanium and titanium tetraisopropoxide which individually are precursors to thin films of titanium nitride and titanium dioxide respectively.

Order of magnitude increase in photocatalytic rate for hierarchically porous anatase thin films synthesized from zinc titanate coatings.

In this paper we report on the use of aerosol assisted chemical vapour deposition (AACVD) to form thin films of the zinc titanate phases using zinc acetate and titanium isopropoxide as precursors in methanol solution. Analysis by XRD and XPS found that through variation in experimental conditions we have been able to synthesize films of zinc titanate with composition of ZnTiO or ZnTiO, which adopt the spinel and pseudobrookite structure respectively. In addition, we have also formed hybrid films of ZnTiO with either ZnTiO or ZnO.

A critical analysis of calcium carbonate mesocrystals.

The term mesocrystal has been widely used to describe crystals that form by oriented assembly, and that exhibit nanoparticle substructures. Using calcite crystals co-precipitated with polymers as a suitable test case, this article looks critically at the concept of mesocrystals. Here we demonstrate that the data commonly used to assign mesocrystal structure may be frequently misinterpreted, and that these calcite/polymer crystals do not have nanoparticle substructures.

Photomagnetic studies on spin-crossover solid solutions containing two different metal complexes, [Fe(1-bpp)(2)](x)[M(terpy)2](1-x)[BF4]2 (M = Ru or Co).

The photomagnetic properties of two series of spin-crossover solid solutions, [Fe(1-bpp)(2)](x)[Ru(terpy)(2)](1-x)(BF(4))(2) and [Fe(1-bpp)(2)](x)[Co(terpy)(2)](1-x)(BF(4))(2) (1-bpp = 2,6-bis[pyrazol-1-yl]pyridine), have been investigated. For all the materials, the evolution of the T(LIESST) value, the high-spin → low-spin relaxation parameters and the LITH loops were thoroughly studied. Interestingly in the Fe:Co series, along the photo-excitation, cobalt ions are concomitantly converted from low-spin to high-spin states with the iron centres, and also fully relax after light excitation.

The use of cationic surfactants to control the structure of zinc oxide films prepared by chemical vapour deposition.

This paper describes a powerful and versatile new method for controlling the structure of zinc oxide thin films prepared by aerosol assisted chemical vapour deposition, based on the use of a common surfactant. The technique combines the benefits of solution and vapour based methods and leads to high quality morphologically-defined and orientated thin films.

An investigation into the optimum thickness of titanium dioxide thin films synthesized by using atmospheric pressure chemical vapour deposition for use in photocatalytic water oxidation.

Twenty eight films of titanium dioxide of varying thickness were synthesised by using atmospheric pressure chemical vapour deposition (CVD) of titanium(IV) chloride and ethyl acetate onto glass and titanium substrates. Fixed reaction conditions at a substrate temperature of 660 °C were used for all depositions, with varying deposition times of 5-60 seconds used to control the thickness of the samples. A sacrificial electron acceptor system composed of alkaline sodium persulfate was used to determine the rate at which these films could photo-oxidise water in the presence of 365 nm light.

The interaction between gold nanoparticles and cationic and anionic dyes: enhanced UV-visible absorption.

The interactions of charge stabilised gold nanoparticles with cationic and anionic dyes are reported. The nanoparticles were synthesised by the Turkevich citrate reduction method. It was found that when a solution of thiazine dye is titrated against gold citrate hydrosol, at a critical concentration of dye there is an enhanced maximum absorption in the dye.

High-throughput continuous hydrothermal synthesis of an entire nanoceramic phase diagram.

A novel High-Throughput Continuous Hydrothermal (HiTCH) flow synthesis reactor was used to make directly and rapidly a 66-sample nanoparticle library (entire phase diagram) of nanocrystalline Ce(x)Zr(y)Y(z)O(2-delta) in less than 12 h. High resolution PXRD data were obtained for the entire heat-treated library (at 1000 degrees C/1 h) in less than a day using the new robotic beamline I11, located at Diamond Light Source (DLS). This allowed Rietveld-quality powder X-ray diffraction (PXRD) data collection of the entire 66-sample library in <1 day.

The use of combinatorial chemical vapor deposition in the synthesis of Ti(3-delta)O4N with 0.06 < delta < 0.25: a titanium oxynitride phase isostructural to anosovite.

We employ, for the first time, a unique combinatorial chemical vapor deposition (CVD) technique to isolate a previously unreported transition-metal mixed-anion phase. The new oxynitride phase, Ti(3-delta)O4N (where 0.06 < delta < 0.

The effect of oxygen-containing reagents on the crystal morphology and orientation in tungsten oxide thin films deposited via atmospheric pressure chemical vapour deposition (APCVD) on glass substrates.

Thin films of monoclinic WO3 and WO(3-x) have been synthesized by atmospheric pressure chemical vapour deposition from WCl6 and three oxygen containing precursors; water, ethanol and ethanoic anhydride. A wide variation in the colour, crystal morphology and preferred orientation of the films was observed, depending on the chosen oxygen source. In particular contrast were the films formed from WCl6 and ethanol, which were blue and had needle-like crystallites, and those formed from WCl6 and water, which were yellow and had hexagonal shaped crystallites.

Topotactic oxidative and reductive control of the structures and properties of layered manganese oxychalcogenides.

Topotactic modification, by both oxidation and reduction, of the composition, structures, and magnetic properties of the layered oxychalcogenides Sr4Mn3O7.5Cu2Ch2 (Ch=S, Se) is described. These Mn3+ compounds are composed of alternating perovskite-type strontium manganese oxide slabs separated by anti-fluorite-type copper chalcogenide layers and are intrinsically oxide deficient in the central layer of the perovskite slabs.

X-ray diffraction area mapping of preferred orientation and phase change in TiO2 thin films deposited by chemical vapor deposition.

This paper reports on an investigation into the formation of TiO(2) thin films, whereby X-ray diffraction is used to map systematic changes in preferred orientation and phase observed throughout the films. The key to this strategy is the recording of X-ray diffraction patterns of specific and isolated areas of a substrate, ensuring this specificity by the use of a small X-ray sample illumination area (approximately 3-5 mm(2)). A map of the variation in film composition can then be built up by recording such diffraction patterns at regular intervals over the whole substrate.

Electronically driven structural distortions in lithium intercalates of the n = 2 Ruddlesden-Popper-type host Y2Ti2O5S2: synthesis, structure, and properties of LixY2Ti2O5S2 (0 < x < 2).

Lithium intercalation into the oxide slabs of the cation-deficient n = 2 Ruddlesden-Popper oxysulfide Y(2)Ti(2)O(5)S(2) to produce Li(x)Y(2)Ti(2)O(5)S(2) (0 < x < 2) is described. Neutron powder diffraction measurements reveal that at low levels of lithium intercalation into Y(2)Ti(2)O(5)S(2), the tetragonal symmetry of the host is retained: Li(0.30(5))Y(2)Ti(2)O(5)S(2), I4/mmm, a = 3.