Publications by authors named "Vasenko A"

Acidic electrochemical CO conversion is a promising alternative to overcome the low CO utilization. However, over-reliance on highly concentrated K to inhibit the hydrogen evolution reaction also causes (bi)carbonate precipitation to interfere with catalytic performance. In this work, under the screening and guidance of computational simulations, we present a carbon coated tip-like InO electrocatalyst for stable and efficient acidic CO conversion to synthesize formic acid (HCOOH) with low K concentration.

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Hybrid lead halide perovskites are promising materials for photovoltaic applications due to their exceptional optoelectronic properties. Here, we investigate the impact of Schottky defects─specifically PbI(V) and CHNHI (V) vacancies─on nonradiative recombination in CHNHPbI using time-dependent density functional theory and nonadiabatic (NA) molecular dynamics. Our results reveal that Schottky defects do not alter the fundamental bandgap or introduce trap states but instead distort the surrounding lattice, localizing the hole distribution.

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Article Synopsis
  • Metal halide perovskites (MHPs) are popular for their low cost and performance, aided by their unique defect dynamics.
  • Research focused on how defects like grain boundaries and lead interstitials create new chemical species that destabilize material properties, preventing recovery to their original structure.
  • Long-lasting defects at grain boundaries negatively affect charge mobility and lifetime, emphasizing the need for effective strategies to manage these defects for improved performance.
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Article Synopsis
  • Metal halide perovskites are advanced materials known for their defect tolerance in carrier recombination, but they face stability issues due to weak lattice interactions leading to ion migration.
  • A study using molecular dynamics and machine learning models shows that ion migration primarily happens at grain boundaries, with Br atoms being the main ones that diffuse after a brief structural change in the grain boundary.
  • Increasing temperature enhances ion migration, and stabilizing the grain boundary by doping or annealing can reduce this migration, offering insights into the material's behavior and stability.
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Nickel-rich layered cathode materials, particularly LiNiMnCoO (NCM811), have garnered significant attention due to their high energy density and impressive electrochemical performance. However, their cycling stability is compromised at elevated voltages, primarily due to structural instability and interfacial degradation. In this study, lithium difluoro(oxalato)borate (LiDFOB) is introduced into a commercial electrolyte based on lithium hexafluorophosphate (LiPF) to elucidate the structural and interfacial changes occurring in NCM811 at a high cut-off voltage of 4.

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Water treatment methods based on cold plasma discharge in cavitating liquid have been actively developing in recent years. However, some conditions, such as the conductivity of the medium, can limit the possibility of plasma ignition. The authors proposed a new method for activating an electric discharge in a cavitating liquid environment based on the use of an external corona discharge electrode in the plasma reactor.

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Double perovskite CsAgBiBr is a promising alternative to lead-based perovskites with excellent stability and attractive optoelectronic properties. However, a relatively large bandgap severely limits its performance in many applications such as solar cells and photodetectors. It has been reported that a random distribution of Ag and Bi atoms in CsAgBiBr effectively reduces its bandgap without introducing dopants or impurities, while the mechanism remains unclear.

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The recent interest in using ultrafast single-photon detectors in research and commercial applications has garnered significant attention from the scientific community. The dynamic event in the detection process consists of a photon causing local destruction of the order parameter, and then the applied current dissipates heat, bringing the material even more out of the superconducting state and then spiking a voltage peak in a measurement device. We investigated the role of superconducting and thermal parameters of the Generalized Time-Dependent Ginzburg-Landau (GTDGL) theory within the event of the first vortex penetration and the thermal dissipation in superconductors near the critical temperature.

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Broadband blue emission in zero-dimensional perovskites has received considerable attention, which is very important for the realization of stable blue-light emitters; however, the underlying formation mechanism remains unclear. Based on first-principles calculations, we have systematically studied the self-trapped excitons (STEs) behavior and luminescence properties in 0D-(DMA)4PbI6 perovskite. Our calculations show that there is a significant difference between the intrinsic STE luminescence mechanism (∼2.

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Nanoscale and condensed matter systems evolve on multiple length- and time-scales, and rare events such as local phase transformation, ion segregation, defect migration, interface reconstruction, and grain boundary sliding can have a profound influence on material properties. We demonstrate how outlier detection indices can be used to identify rare events in machine-learning based, high-dimensional molecular dynamics (MD) simulations. Designed to order data-points from typical to untypical, the indices enable one to capture atomic events that are hard to detect otherwise.

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The development of ultrathin magnets with tunable magnetic properties is essential for advancing quantum computing technologies. In this study, density functional theory (DFT) calculations were employed to investigate the atomic and electronic structures of a ZnO monolayer embedded with cobalt atoms. The impact of spin dynamics on charge transfer within the Co:ZnO system was thoroughly examined.

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The temperature and the coordination environment significantly affect polaron dynamics. Using goethite (FeOOH) as a model, our study examines polaron formation and recombination behavior under various conditions, including electron injection, photoexcitation, and heterovalent doping. Ab initio and nonadiabatic molecular dynamics (NAMD) simulations reveal that polaron formation in FeOOH is dependent on temperature via an adiabatic mechanism with higher temperatures leading to shorter formation times.

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Article Synopsis
  • A search for dark matter candidates in the mass range of 65 to 1021 keV was conducted using data from the GERDA experiment, focusing on energy depositions without detecting any significant signals above background noise.
  • The study established stringent exclusion limits on dark photon and axion-like particle interactions with electrons, with specific constraints noted at a 150 keV mass level.
  • Additional investigations into the decay rates of nucleons and electrons yielded lower lifetime limits for neutron, proton, and electron decay events at a 90% confidence interval.
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Nonadiabatic molecular dynamics (NA-MD) is a powerful tool to model far-from-equilibrium processes, such as photochemical reactions and charge transport. NA-MD application to condensed phase has drawn tremendous attention recently for development of next-generation energy and optoelectronic materials. Studies of condensed matter allow one to employ efficient computational tools, such as density functional theory (DFT) and classical path approximation (CPA).

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Non-adiabatic (NA) molecular dynamics (MD) is a powerful approach for studying far-from-equilibrium quantum dynamics in photophysical and photochemical systems. Most NA-MD methods are developed and tested with few-state models, and their validity with complex systems involving many states is not well studied. By modeling intraband equilibration and interband recombination of charge carriers in MoS2, we investigate the convergence of three popular NA-MD algorithms, fewest switches surface hopping (FSSH), global flux surface hopping (GFSH), and decoherence induced surface hopping (DISH) with the number of states.

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In this work, a solid-state method for the synthesis of perovskite La(FeCuMnMgTi)O high-entropy oxide (HEO) nanoparticles is detailed. Additionally, the high performance of these nanoparticles as catalysts in the aerobic and solvent-free oxidation of benzyl alcohol is demonstrated. The structural features of HEO nanoparticles are studied by X-ray diffraction and high-resolution transmission electron microscopy.

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Heterojunctions of metal oxides have attracted a great deal of attention as photo (electro) catalysts owing to their excellent photoactivity. While multiple fundamental studies have been dedicated to heteroaggregation, self-assembly of oppositely charged particles to obtain heterojunctions for energy applications has been underexplored. Herein, we report the synthesis of ZnO-TiO heterojunctions using the electrostatic self-assembly approach.

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Bismuth iodide perovskite nanocrystals are considered a viable alternative to the Pb halide ones due to their reduced toxicity and increased stability. However, it is still challenging to fabricate nanocrystals with a small and controlled size, and their electronic properties are not well understood. Here, we propose the growth of Bi iodide perovskite nanocrystals using different mesoporous silica with ordered pores of controlled diameter as templates.

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In this work, La(FeCuMnMgTi)O HEO nanoparticles with a perovskite-type structure are synthesized and used in the electrocatalytic CO reduction reaction (CORR). The catalyst demonstrates high performance as an electrocatalyst for the CORR, with a Faradaic efficiency (FE) of 92.5% at a current density of 21.

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Grain boundaries (GBs) play an important role in determining the optoelectronic properties of perovskites, requiring an atomistic understanding of the underlying mechanisms. Strain engineering has recently been employed in perovskite solar cells, providing a novel perspective on the role of perovskite GBs. Here, we theoretically investigate the impact of axial strain on the geometric and electronic properties of a common CsPbBr GB.

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Further improving the activity and selectivity of photocatalytic CO reduction remains a challenge. Herein, we propose a new strategy for synergistically promoting photocatalytic CO reduction by combining two-dimensional (2D) ferroelectric polarization and single-atom catalysis. Our calculations showed that the ferroelectric polarization of CuBiPSe provides the internal driving force for the separation and migration of photogenerated carriers, which provides a prerequisite for enhancing the photocatalytic efficiency.

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The rapid recombination of photogenerated carriers heavily restricts the photocatalytic efficiency. Here, we propose a new strategy to improve catalytic efficiency based on the ferroelectric van der Waals heterostructure (CuBiPSe/CN). Combining density functional theory and the nonadiabatic molecular dynamics (NAMD) method, we have systematically analyzed the ground-state properties and carrier dynamics images in the CuBiPSe/CN heterostructure.

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Rechargeable aprotic Li-CO batteries have aroused worldwide interest owing to their environmentally friendly CO fixation ability and ultra-high specific energy density. However, its practical applications are impeded by the sluggish reaction kinetics and discharge product accumulation during cycling. Herein, a flexible composite electrode comprising CoSe nanoparticles embedded in 3D carbonized melamine foam (CoSe/CMF) for Li-CO batteries is reported.

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A theoretical model for an electrical discharge in a cavitating liquid is developed and compared with experiments for the optimization of the water treatment device. The calculations based on solution of the Noltingk─Neppiras equation support the hypothesis that the electric field promotes the formation of vapor microchannels inside a liquid gap between the electrodes, where at a low gas pressure Paschen's conditions of rupture and abnormal glow discharge maintenance in those microchannels are fulfilled. Theoretical analysis of the cavitation processes and the discharge formation processes is in qualitative agreement with the experimental data obtained in this work in a water treatment device using a hydrodynamic emitter.

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Doping of zinc oxide (ZnO) with manganese (Mn) tunes midbandgap states of ZnO to enhance its optical properties and makes it into an efficient photoactive material for photoelectrochemical water splitting, waste removal from water, and other applications. We demonstrate that ZnO modified with 1 at. % Mn exhibits the best performance, as rationalized by experimental, structural, and optical characterization and theoretical analysis.

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