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Electron temperature is reconsidered for weakly-ionized oxygen and nitrogen plasmas with its discharge pressure of a few hundred Pa, with its electron density of the order of 1017m−3 and in a state of non-equilibrium, based on thermodynamics and statistical physics. The relationship between entropy and electron mean energy is focused on based on the electron energy distribution function (EEDF) calculated with the integro-differential Boltzmann equation for a given reduced electric field E/N. When the Boltzmann equation is solved, chemical kinetic equations are also simultaneously solved to determine essential excited species for the oxygen plasma, while vibrationally excited populations are solved for the nitrogen plasma, since the EEDF should be self-consistently found with the densities of collision counterparts of electrons. Next, the electron mean energy U and entropy S are calculated with the self-consistent EEDF obtained, where the entropy is calculated with the Gibbs’s formula. Then, the “statistical” electron temperature Test is calculated as Test=[∂S/∂U]−1. The difference between Test and the electron kinetic temperature Tekin is discussed, which is defined as [2/(3k)] times of the mean electron energy U=⟨ϵ⟩, as well as the temperature given as a slope of the EEDF for each value of E/N from the viewpoint of statistical physics as well as of elementary processes in the oxygen or nitrogen plasma.

Photocatalytic oxidation techniques are promising for degradation of the highly ecotoxic and refractory isothiazolinone bactericides in relevant industrial wastewaters. However, low charge separation and directional transport efficiency under solar light radiation restrain their practical application. Here, we report a nanostructured photocatalyst doped with Gd and B in TiO 2 with carbon incorporation and defect formation through incomplete calcination. The specific surface area, grain size, and hydrophilicity of TiO 2 are improved, which is beneficial for the interfacial reaction between the photocatalyst and pollutants. The reduction of the bandgap, the broadening of the photo-absorption range, and the retarded electron-hole recombination promote the photocatalytic performance due to the improved oxygen vacancies based on the electron distribution modification. The difference in partial density of states (ΔPDOS) between the current catalyst and raw TiO 2 indicates that the co-doping of Gd and B with incomplete calcination changes the electronic hybridization of conduction band and valence band near the Fermi level, and affects the band gap energy. It improved charge separation and directional transport efficiency and benefited the formation of main active species, including OH and O 2 − , for the pollutant decomposition. The rate of photocatalytic removal of benzisothiazolinone (BIT) by the current photocatalyst reaches 1.25 h −1 , being 4.31 times that of TiO 2 . The current work offers a constructive approach to the design and synthesis of nanostructured photocatalysts for the photocatalytic degradation of refractory organic pollutants.

We investigate photocurrents driven by femtosecond laser excitation of a (sub)-nanometer tunnel junction in an ultrahigh vacuum low-temperature scanning tunneling microscope (STM). The optically driven charge transfer is revealed by tip retraction curves showing a current contribution for exceptionally large tip-sample distances, evidencing a strongly reduced effective barrier height for photoexcited electrons at higher energies. Our measurements demonstrate that the magnitude of the photo-induced electron transport can be controlled by the laser power as well as the applied bias voltage. In contrast, the decay constant of the photocurrent is only weakly affected by these parameters. Stable STM operation with photoelectrons is demonstrated by acquiring constant current topographies. An effective non-equilibrium electron distribution as a consequence of multiphoton absorption is deduced by the analysis of the photocurrent using a one-dimensional potential barrier model.

The tailoring of the charge transfer between support material and transition metal active phase is an effective strategy for fine tuning the electronic structure of the catalyst active site, and hence improving the activity and stability of the reaction. This works presents that Co nanoparticles supported on N‐doped mesoporous hollow carbon nanospheres (Co/NMHCS) decouple the effect of electronic structure on catalytic performance. The detailed experimental and theoretical results reveal the charge distribution at the Co/NMHCS interface due to N‐doped MHCS. With tuning the electron redistribution, the interface between Co nanoparticles and NMHCS as the active site shows the strong capability to adsorb and reduce the OOH* and proton, thus leading to the optimal ORR, OER, and HER activity in Co/NMHCS. Furthermore, Co/NMHCS‐based Zn–air battery exhibits high power density of 185 mW cm−2, and high gravimetric energy density of 753 mAh gZn−1. Density functional theory (DFT) reveals the electrons accumulate directly on the NMHCS support, which originates from an interplay between Co nanoparticles and the NMHCS support. This work provides constructive guidance for precisely regulating the interface electronic structures to achieve excellent electrocatalytic performance. Interfacial electron distribution Co nanoparticles supported on N‐doped mesoporous for ORR, OER, and HER via pre‐precipitation method followed by thermal treatment strategy is investigated. Such Co nanoparticles supported on N‐doped mesoporous catalysts also exhibit remarkable performance for Zn–air batteries and overall water splitting. This work paves a new way for constructing electrocatalysts in electrochemical energy devices.

One of the most important characteristics of low-temperature plasma is the electron energy distribution function (EEDF) or the velocity distribution function. This work examines the influence of the electromagnetic field on the values of the electron velocity distribution function (EVDF) at pressures from 13.3 to 133 Pa for electric field strengths from −3000 to 3000 V/m in a radiofrequency (RF) discharge with a degree of ionization of 10 −6 –10 −4 . It has been shown that at low frequencies of the RF electromagnetic field (0.44–1.76 MHz) and a decrease in the collision frequency to 5 × 10 7 Hz, the deviation of the EVDF from the Maxwellian EVDF comes to 35% with an increase in the absolute value of field strength to 3000 V/m. This has a significant impact on the diffusion and mobility coefficients, the difference in which can be up to 25% in the considered range of parameters.

Based on the kinetic approach, this work investigates the stability of the system consisting of a fast electron beam and a dense plasma at an arbitrary (anisotropic) electron velocity distribution function. It is shown that during the interaction of a fast electron beam with a cold plasma, both the conditions for losing stability and the growth rate of disturbances do not depend on the form of the electron distribution function (EDF) of a plasma and are determined only by the ratio of the electron beam energy to the mean energy in a plasma. With an increase in the mean electron energy in the plasma, it becomes necessary to take into account the following energy moments of the EDF. It was found that the plasma anisotropy has a significant effect on both the stability loss conditions and the growth rate. The physical reason for this effect is the shift in the plasma frequency due to the Doppler effect caused by the plasma anisotropy in the coordinate system moving along with the beam. Other findings include a region of anomalous dispersion of the electron beam–plasma system and regions of negative group velocity of perturbations in such system. Physical interpretations are proposed for all the observed effects.

The development of materials for clean and efficient energy generation and storage is one of the most rapidly developing, multi-disciplinary areas of contemporary science, driven primarily by concerns over global warming, diminishing fossil-fuel reserves, the need for energy security, and increasing consumer demand for portable electronics. Computational methods are now an integral and indispensable part of the materials characterisation and development process.   Computational Approaches to Energy Materials presents a detailed survey of current computational techniques for the development and optimization of energy materials, outlining their strengths, limitations, and future applications.  The review of techniques includes current methodologies based on electronic structure, interatomic potential and hybrid methods. The methodological components are integrated into a comprehensive survey of applications, addressing the major themes in energy research. Topics covered include: • Introduction to computational methods and approaches • Modelling materials for energy generation applications: solar energy and nuclear energy • Modelling materials for storage applications: batteries and hydrogen • Modelling materials for energy conversion applications: fuel cells, heterogeneous catalysis and solid-state lighting • Nanostructures for energy applications This full colour text is an accessible introduction for newcomers to the field, and a valuable reference source for experienced researchers working on computational techniques and their application to energy materials.

Linear and nonlinear propagation characteristics of drift ion acoustic waves are analyzed in an inhomogeneous plasma comprising of warm ions having shear flow parallel to the magnetic field and electrons that are followed by a distribution which is dictated by spectral indices, r and q in low and high phase density regions. In the linear regime, the dispersion relation of the drift-ion acoustic wave is derived and the condition for the onset of shear flow instability is presented. It is found that condition for the emergence of shear flow instability gets modified by generalized (r,q) distribution and ion to electron temperature ratio. In the nonlinear regime, vortex formation with non-Maxwellian electron distribution is investigated and the effects of low and high energy electrons in this context are explored in detail. Interestingly, it is found that unlike the dipolar vortices, the electrons in the high phase space density regions do not significantly affect the Kelvin-Stuart’s cat’s eyes structures, however, the converse is true for the electrons belonging to the regions of low phase space density. Estimates of the size of these vortex structures in space plasmas are also given where the distribution function presented here is frequently encountered.

We study the electron charge distribution on a quasiperiodic tiling in terms of hyperuniformity. In an extended Hubbard model on the Ammann-Beenker tiling, the electron distribution changes significantly with the Fermi energy and electron-interaction strength. Unlike periodic systems, these changes are not characterized by translational-symmetry breaking. We show that the electron charge distribution is not characterized by multifractality, either. We find that the distribution is instead characterized by hyperuniformity of Class I.

We experimentally extracted the positive bias temperature stress (PBTS)-induced trapped electron distribution within the gate dielectric in self-aligned top-gate (SA-TG) coplanar indium–gallium–zinc oxide (IGZO) thin-film transistors (TFTs) using the analytical threshold voltage shift model. First, we carefully examined the effects of PBTS on the subgap density of states in IGZO TFTs to exclude the effects of defect creation on the threshold voltage shift due to PBTS. We assumed that the accumulated electrons were injected into the gate dielectric trap states near the interface through trap-assisted tunneling and were consequently moved to the trap states, which were located further away from the interface, through the Poole–Frenkel effect. Accordingly, we quantitatively analyzed the PBTS-induced electron trapping. The experimental results showed that, in the fabricated IGZO TFTs, the electrons were trapped in the shallow and deep trap states simultaneously owing to PBTS. Electrons trapped in the shallow state were easily detrapped after PBTS termination; however, those trapped in the deep state were not. We successfully extracted the PBTS-induced trapped electron data within the gate dielectric in the fabricated SA-TG coplanar IGZO TFTs by using the proposed method.