Chalcogen Doping in SnO: A DFT Investigation of Optical and Electronic Properties for Enhanced Photocatalytic Applications.

Tin dioxide (SnO) is an important transparent conductive oxide (TCO), highly desirable for its use in various technologies due to its earth abundance and non-toxicity. It is studied for applications such as photocatalysis, energy harvesting, energy storage, LEDs, and photovoltaics as an electron transport layer. Elemental doping has been an established method to tune its band gap, increase conductivity, passivate defects, etc.

Vanadium and tantalum doping of tin dioxide: a theoretical study.

The increasing demand of efficient optoelectronic devices such as photovoltaics has created a great research interest in methods to manipulate the electronic and optical properties of all the layers of the device. Tin dioxide (SnO), due to his charge transport capability, high stability and easy fabrication is the main electron transport layer in modern photovoltaics which have achieved a record efficiency. While the wide band gap of SnO makes it an effective electron transport layer, its potential for other energy applications such as photocatalysis is limited.

Efficient and Stable Air-Processed Ternary Organic Solar Cells Incorporating Gallium-Porphyrin as an Electron Cascade Material.

Two gallium porphyrins, a tetraphenyl GaCl porphyrin, termed as (TPP)GaCl, and an octaethylporphyrin GaCl porphyrin, termed as (OEP)GaCl, were synthesized to use as an electron cascade in ternary organic bulk heterojunction films. A perfect matching of both gallium porphyrins' energy levels with that of poly(3-hexylthiophene-2,5-diyl) (P3HT) or poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT) polymer donor and the 6,6-phenyl C butyric acid methyl ester (PCBM) fullerene acceptor, forming an efficient cascade system that could facilitate electron transfer between donor and acceptor, was demonstrated. Therefore, ternary organic solar cells (OSCs) using the two porphyrins in various concentrations were fabricated where a performance enhancement was obtained.

Optical Response, Lithium Doping, and Charge Transfer in Sn-Based 312 MAX Phases.

The optical response, lithium doping, and charge transfer in three Sn-based existing MSnC MAX phases with electron localization function (ELF) were investigated using density functional theory (DFT). Optical calculations show a slight optical anisotropy in the spectra of different optical parameters in some energy ranges of the incident photons. The peak height is mostly slightly higher for the polarization ⟨001⟩.

Carbon Nanodots as Electron Transport Materials in Organic Light Emitting Diodes and Solar Cells.

Charge injection and transport interlayers play a crucial role in many classes of optoelectronics, including organic and perovskite ones. Here, we demonstrate the beneficial role of carbon nanodots, both pristine and nitrogen-functionalized, as electron transport materials in organic light emitting diodes (OLEDs) and organic solar cells (OSCs). Pristine (referred to as C-dots) and nitrogen-functionalized (referred to as NC-dots) carbon dots are systematically studied regarding their properties by using cyclic voltammetry, Fourier-transform infrared (FTIR) and UV-Vis absorption spectroscopy in order to reveal their energetic alignment and possible interaction with the organic semiconductor's emissive layer.

Defects, diffusion and dopants in LiSnO.

Octalithium tin (IV) oxide (LiSnO) is an important electrode material considered for lithium ion batteries (LIBs) because of its high lithium content. We employed atomistic simulations to examine the intrinsic defects, diffusion of Li-ions together with their migration energies and solution of potential dopants in LiSnO. The most thermodynamically favourable intrinsic defect is the Li Frenkel which increases the concentration of Li vacancies needed for the vacancy mediated diffusion of Li-ions in LiSnO.

Impact of boron and indium doping on the structural, electronic and optical properties of SnO.

Tin dioxide (SnO), due to its non-toxicity, high stability and electron transport capability represents one of the most utilized metal oxides for many optoelectronic devices such as photocatalytic devices, photovoltaics (PVs) and light-emitting diodes (LEDs). Nevertheless, its wide bandgap reduces its charge carrier mobility and its photocatalytic activity. Doping with various elements is an efficient and low-cost way to decrease SnO band gap and maximize the potential for photocatalytic applications.

Preparation of hydrogen, fluorine and chlorine doped and co-doped titanium dioxide photocatalysts: a theoretical and experimental approach.

Titanium dioxide (TiO) has a strong photocatalytic activity in the ultra-violet part of the spectrum combined with excellent chemical stability and abundance. However, its photocatalytic efficiency is prohibited by limited absorption within the visible range derived from its wide band gap value and the presence of charge trapping states located at the band edges, which act as electron-hole recombination centers. Herein, we modify the band gap and improve the optical properties of TiO via co-doping with hydrogen and halogen.

Self-diffusion in garnet-type LiLaZrO solid electrolytes.

Tetragonal garnet-type LiLaZrO is an important candidate solid electrolyte for all-solid-state lithium ion batteries because of its high ionic conductivity and large electrochemical potential window. Here we employ atomistic simulation methods to show that the most favourable disorder process in LiLaZrO involves loss of LiO resulting in lithium and oxygen vacancies, which promote vacancy mediated self-diffusion. The activation energy for lithium migration (0.

Electronegativity and doping in SiGe alloys.

Silicon germanium alloys are technologically important in microelectronics but also they are an important paradigm and model system to study the intricacies of the defect processes on random alloys. The key in semiconductors is that dopants and defects can tune their electronic properties and although their impact is well established in elemental semiconductors such as silicon they are not well characterized in random semiconductor alloys such as silicon germanium. In particular the impact of electronegativity of the local environment on the electronic properties of the dopant atom needs to be clarified.

Defect processes in F and Cl doped anatase TiO.

Titanium dioxide represents one of the most widely studied transition metal oxides due to its high chemical stability, non-toxicity, abundance, electron transport capability in many classes of optoelectronic devices and excellent photocatalytic properties. Nevertheless, the wide bang gap of pristine oxide reduces its electron transport ability and photocatalytic activity. Doping with halides and other elements has been proven an efficient defect engineering strategy in order to reduce the band gap and maximize the photocatalytic activity.

Stability of Coinage Metals Interacting with C.

Buckminsterfullerene (C) has been advocated as a perfect candidate material for the encapsulation and adsorption of a variety of metals and the resultant metallofullerenes have been considered for the use in different scientific, technological and medical areas. Using spin-polarized density functional theory together with dispersion correction, we examine the stability and electronic structures of endohedral and exohedral complexes formed between coinage metals (Cu, Ag and Au) and both non-defective and defective C. Encapsulation is exoergic in both forms of C and their encapsulation energies are almost the same.

Defect Chemistry, Sodium Diffusion and Doping Behaviour in NaFeO Polymorphs as Cathode Materials for Na-Ion Batteries: A Computational Study.

Minor metal-free sodium iron dioxide, NaFeO, is a promising cathode material in sodium-ion batteries. Computational simulations based on the classical potentials were used to study the defects, sodium diffusion paths and cation doping behaviour in the α- and β-NaFeO polymorphs. The present simulations show good reproduction of both α- and β-NaFeO.

The encapsulation selectivity for anionic fission products imparted by an electride.

The nanoporous oxide 12CaO·7AlO (C12A7) can capture large concentrations of extra-framework species inside its nanopores, while maintaining its thermodynamical stability. Here we use atomistic simulation to predict the efficacy of C12A7 to encapsulate volatile fission products, in its stoichiometric and much more effective electride forms. In the stoichiometric form, while Xe, Kr and Cs are not captured, Br, I and Te exhibit strong encapsulation energies while Rb is only weakly encapsulated from atoms.

Defects, Diffusion, and Dopants in LiTiO: Atomistic Simulation Study.

In this study, force field-based simulations are employed to examine the defects in Li-ion diffusion pathways together with activation energies and a solution of dopants in LiTiO. The lowest defect energy process is found to be the Li Frenkel (0.66 eV/defect), inferring that this defect process is most likely to occur.

Impact of local composition on the energetics of E-centres in SiGe alloys.

The energetics of the defect chemistry and processes in semiconducting alloys is both technologically and theoretically significant. This is because defects in semiconductors are critical to tune their electronic properties. These processes are less well understood in random semiconductor alloys such as silicon germanium as compared to elementary semiconductors (for example silicon).

Technetium Encapsulation by A Nanoporous Complex Oxide 12CaO•7AlO (C12A7).

Technetium (Tc) is an important long-lived radionuclide released from various activities including nuclear waste processing, nuclear accidents and atmospheric nuclear weapon testing. The removal of Tc from the environment is a challenging task, and chemical capture by stable ceramic host systems is an efficient strategy to minimise the hazard. Here we use density functional theory with dispersion correction (DFT+D) to examine the capability of the porous inorganic framework material C12A7 that can be used as a filter material in different places such as industries and nuclear power stations to encapsulate Tc in the form of atoms and dimers.

Defect Chemistry and Na-Ion Diffusion in NaFe(PO) Cathode Material.

In this work, we employ computational modeling techniques to study the defect chemistry, Na ion diffusion paths, and dopant properties in sodium iron phosphate [NaFe(PO)] cathode material. The lowest intrinsic defect energy process (0.45 eV/defect) is calculated to be the Na Frenkel, which ensures the formation of Na vacancies required for the vacancy-assisted Na ion diffusion.

Defects, dopants and Mg diffusion in MgTiO.

Magnesium titanate is technologically important due to its excellent dielectric properties required in wireless communication system. Using atomistic simulation based on the classical pair potentials we study the defect chemistry, Mg and O diffusion and a variety of dopant incorporation at Mg and Ti sites. The defect calculations suggest that cation anti-site defect is the most favourable defect process.

Defects, Lithium Mobility and Tetravalent Dopants in the LiNbO Cathode Material.

The defect processes of oxides such as self-diffusion impact their performance in electrochemical devices such as batteries and solid oxide fuel cells. The performance of lithium ion batteries can be improved by increasing the Li-ion diffusion. In that respect LiNbO is identified as a positive electrode material for rechargeable lithium ion batteries.

Defect Chemistry and Li-ion Diffusion in LiRuO.

Layered LiRuO is an important candidate cathode material in rechargeable lithium ion batteries because of its novel anionic redox process and high reversible capacity. Atomistic scale simulations are used to calculate the intrinsic defect process, favourable dopants and migration energies of lithium ion diffusions together with migration paths in LiRuO. The Li Frenkel is calculated to be the most favourable intrinsic defect type.

Defects and dopant properties of LiV(PO).

Polyanion phosphate based LiV(PO) material has attracted considerable attention as a novel cathode material for potential use in rechargeable lithium ion batteries. The defect chemistry and dopant properties of this material are studied using well-established atomistic scale simulation techniques. The most favourable intrinsic defect process is the Li Frenkel (0.