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Understanding the structures and energetics of vacancy-type defects is crucial for comprehending defect evolution in metals, yet current methods face significant challenges, particularly regarding nanovoids in FCC metals. Here, we developed a robust modeling framework to accurately predict the structure and energetics of nanovoids in FCC metals. We demonstrated that stable nanovoid structures can be efficiently determined by maximizing the coordination number among vacancies and identified a linear relationship between nanovoid formation energies and their compactness factors. Notably, we revealed six discrete binding energy levels in nanovoid-vacancy interactions, each correlated solely with changes in compactness factors. Our new model has been validated through first-principles calculations and experiments, demonstrating clear advantages over conventional methods. This model effectively handles arbitrarily sized nanovoids in FCC metals, capturing atomic-scale variations, and providing key insights into vacancy-related damage, along with essential tools for multiscale modeling and the development of new metal interatomic potentials.

In this work, the adsorption behaviors of DNA nucleobases molecules on pristine, defective Ti2N and oxygenfunctionalized Ti2NO2 have been investigated using the Density Functional Theory (DFT) within the framework of Van der Waals corrections. It is found that the pristine Ti2N has intense adsorption energy, which is decreased by approaches such as introducing Ti/N defects or attaching the oxygen functional group. Through studies of the equilibrium geometrical configurations, partial density of states, band structure, Bader charge analysis, charge density difference and work function, it is indicated that the adsorption strength of pristine Ti2N towards DNA nucleobases is stronger than defective Ti2N and Ti2NO2. While, in terms of decreasing the recovery time, Ti2NO2 is the best candidate among them for the sensing of DNA nucleobases. This theoretical work is proposed to provide guidance for experimentalists to develop better 2-D sensing materials to detect DNA nucleobases molecules for bio-medical applications in the future.

Silks derived from spiders and silkworm cocoons represent a unique class of protein-based multifunctional materials characterized by exceptional mechanical, biological, and structural properties. Here, we review recent progress in understanding the silk material system, highlight its hierarchical molecular structure and discuss an atomistic model of silk and its success in explaining unique mechanical and optoelectronic properties. We summarize the extraordinary tensile and unique torsional properties of silks and their remarkable resilience under extreme conditions, such as cryogenic temperatures and high vacuum. A notable advancement is in nano-processing and heterostructuring of silk fibres using intense femtosecond pulses. This technique facilitated the development of anew class of nano-scale force and torque silk-based sensors operating in air or vacuum and offering high sensitivity. Additionally, cocoon silk, specifically the protein fibroin, is highlighted as a bulk material with significant potential for the fabrication of optical components and both active and passive optoelectronic devices for biomedical applications. Finally, we point out key challenges in this field, such as achieving a complete atomistic understanding of silk materials and discuss emerging opportunities for silk-based functional technological applications.

The increase in the use of alternative energies depends on efficient ways to store the energy generated by intermittent renewable sources such as the sun and wind. Li batteries are among the most used strategies to fulfill this task, but improvements in the efficiency and safety of these Li devices are still required. In this work, the density functional theory was used to study the adequacy of boron phosphide nanotubes as active anodes in Li batteries. Using the (5,5) nanotube as a prototype it is shown that these thermodynamically stable nanotubes can adsorb Li atoms at all of their hollow sites with binding energies around 0.12 eV. For an increasing number of adsorbed Li atoms, a tendency to Li clusterization is observed. Further, the Li adsorption is accompanied by a significant distortion of the nanotube structure, which is seen to be reversible when the nanotube is delithiated. A relatively low activation barrier, 0.19 eV, for Li diffusion on the nanotube surface is determined. Open circuit voltages of approximate to 0.10 V, and theoretical specific capacities of 641 mAh/g are obtained, showing that these nanotubes are promising candidates for anodes in Li batteries

We have performed systematic electronic structure calculations based on reaction coordinate construction and charge transfer analysis to explore the demarcation between two-competing mechanisms: the electrochemical nitrogen reduction reaction (eNRR) and hydrogen evolution reaction (HER). We have employed density functional theory based first-principles calculations to investigate the eNRR and HER on the cuboidal silver phosphate Ag₃PO₄ surface in an acidic medium. For the eNRR, we have explored all three reaction mechanism pathways named distal, alternating and enzymatic, while the adsorption site selectivity has also been envisaged in this work. Among all the possible catalytic sites of Ag₃PO₄, the Ag site turned out to be the most energetically favourable for the eNRR that suppresses HER activity. The alternating pathway is confirmed to be the best catalytic pathway with a limiting potential of -0.60 V, as compared to -1.4 V and -2.9 V for distal and enzymatic pathways, respectively. The quantitative and qualitative analyses of the charge transfer process corresponding to the alternating pathway of the eNRR are also being explored from the perspective of Bader charge variation and charge density distribution.

Photocatalytic water splitting has attracted extensive attention for its bright prospects in producing clean hydrogen energy. To realize efficient solar-to-hydrogen energy conversion, it is important to explore a photocatalyst with high electron-hole separation and wide-range solar absorption. Herein, a novel twodimensional metal-hydride, LuH₃, is designed and its viability as an efficient photocatalyst for overall water splitting is evaluated in the present work. It reveals that LuH₃ monolayer is an isotropic semiconductor with a direct band gap of 2.56 eV, decreased to 1.872 eV in a bilayer, exhibiting strong absorption efficiency for ultraviolet, visible, and near-infrared regions. Besides, it has favorable valence and conduction band positions for water redox reactions of O₂/H₂O and H⁺/H₂, high carrier mobility, and significant charge separation capability due to the orientation-dependent distribution in band edges, which play vital roles to enhance photocatalytic performance. The higher partial charge densities on H_1b and H_2d in HOMO lead to amore potent oxidation reaction, facilitating the reduction reaction and the production of hydrogen. In particular, LuH3 monolayer is flexible and sensitive to external stress. Applying both isotropic and uniaxial strain has a limited impact on achieving favorable band alignments with water redox potentials, providing distinct opportunities for various applications. In both acidic and alkaline environments, LuH3 monolayer shows significant potential for efficient photocatalysis in the context of overall water splitting. Furthermore, LuH3, a van der Waals material, can exfoliate from multilayered or bulk forms with a cleavage energy of 1.07 J/m², which is three times higher than the experimentally measured 0.37 J/m² for graphite. These findings highlight the potential of LuH₃ monolayer as an efficient solar-spectrum water-splitting photocatalyst, with implications for sustainable energy conversion technologies utilizing solar energy for clean and renewable hydrogen fuel generation.

The prevalence of compost and its integration within the bio-circular economy, facilitating the seamless conversion of bio-waste into compost, present an auspicious avenue for the exploration of renewable energy storage solutions. Thus, the current study investigates the effect of electrolytes on faradic and non-faradic processes of charge storage in a symmetrical device design based on compost. The inquiry examines the composts as an electrode material and the influence of various current collectors (G-G, Cu-Cu and IN-IN) across distinct aqueous electrolyte environments (1 M KNO3, 1 M KCl and 1 M KOH). The findings reveal the composts' capacity to accommodate both capacitive and non-capacitive charge storage processes within a symmetric dual-current collector apparatus, showcasing the multifaceted charge storage modalities akin to those observed in capacitors and batteries. The electrochemical assessments, conducted through cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) profiling, and electrochemical impedance spectroscopy (EIS), elucidate the non-faradaic and faradaic charge storage mechanisms in terms of the charge storage efficiency, temporal characteristics of the charge and discharge cycle, specific capacitance, and specific capacity. The results obtained evince the superior charge storage capabilities of the compost samples across various electrolyte solutions relative to the aqueous media. The compost specimen featuring a C:N ratio of 145.44 in a 1 M KCl solution assembled in a symmetric G-G current collectors device exhibited the optimal electrochemical performance. At a scan rate of 100 mV/s within a potential window of +/- 4.5 V, the CV studies exhibited an area under the curve of 3.3142C, a specific capacitance of 18.4mF/g and a specific capacity of 82.8 mC/g, while the GCD studies were characterised by a charging time of 51 s, a discharging time of 47.2 s, a specific capacitance of 10.4 mF/g and a specific capacity of 94.4 mC/g at an applied current of 400 mA within a potential window of +/- 4.5 V.

In the past few decades, two-dimensional materials gained huge deliberation due to their outstanding electronic and heat transport properties. These materials have effective applications in many areas such as photodetectors, battery electrodes, thermoelectrics, etc. In this work, we have calculated structural, electronic, optical, and thermoelectric (TE) properties of KCuX (X = S, Se, Te) monolayers (MLs) with the help of first-principles-based calculations and semi-classical Boltzmann transport equation. The phonon dispersion calculations demonstrate the dynamical stability of the KCuX (X = S, Se, Te) MLs. Our results show that the MLs of KCuX (X = S, Se, Te) are semiconductors with band gaps of 0.193 eV, 0.26 eV, and 1.001 eV respectively, and therefore they are suitable for photovoltaic applications. The optical analysis illustrates that the maximum absorption peaks of the KCuX (X = S, Se, Te) MLs are located in the visible and ultraviolet regions, which may serve as a promising candidate for designing advanced optoelectronic devices. Furthermore, thermoelectric properties of the KCuS and KCuSe MLs, including Seebeck coefficient, electrical conductivity, electronic thermal conductivity, power factor and figure of merit are calculated at different temperatures of 300 K, 600 K, and 800 K. Additionally, we also focus on the analysis of Gr & uuml;neisen parameter and various scattering rates to further explain their ultra-low thermal conductivity. Our results show that KCuS and KCuSe possess ultra-low lattice thermal conductivity value of 0.15 Wm(-1)K(-1) and 0.06 Wm(-1)K(-1) respectively, which is lower than those of recently reported KAgSe (0.26 Wm-1K-1 at 300 K) and TlCuSe (0.44 Wm(-1)K(-1) at 300 K), indicating towards the large value of ZT. These materials are found to possess desirable thermoelectric and optical properties, making them suitable candidates for efficient thermoelectric and optoelectronic device applications.

Half-metallic magnets with high Curie temperatures (Tc) are essential for the advancement of next-generation spintronic technologies. In this study, we perform a comprehensive first-principles investigation of the CoAl2Se4 monolayer, an AM2X4-type material that has remained largely unexplored. Our findings confirm its energetic, mechanical, and dynamical stability, as evidenced by cohesive and formation energy calculations, elastic constants, and phonon dispersion analysis. The observed ferromagnetic behavior arises from Co-Se-Co bond superexchange interactions, in agreement with the Goodenough-Kanamori rules. The monolayer exhibits robust half-metallicity, characterized by a substantial half-metallic gap of 2.76 eV, enabling fully spin-polarized electronic conduction. Magnetic anisotropy energy calculations indicate an easy-plane magnetization, while Monte Carlo simulations predict a high Curie temperature of 431 K, well above room temperature, ensuring stable magnetic ordering under ambient conditions. These outstanding properties position the CoAl2Se4 monolayer as a promising candidate for spin filtering devices, magnetoresistive sensors, and next-generation magnetic memory technologies.

The optimized atomic structures, energetics and electronic structures of ethylbenzene adsorption systems on pristine, doped and vacancy-defective Ti₂C nanosheets respectively have been investigated using first-principles method based on density functional theory to explore their potential ethylbenzene adsorption and detection capabilities. It is found that various vacancy defects improve the ethylbenzene adsorption energies of Ti₂C nanosheet. While, the adsorption behavior of ethylbenzene molecule on doped Ti₂C nanosheet varies with the difference of doping atoms. Among them, the Si-doped and Mn-doped Ti₂C respectively show good adsorption potential. Charge transfer mechanisms between ethylbenzene and various Ti₂C nanosheets have been studied through the Bader charge and differential charge density analysis to explore the deep origin of the underlying electronic structure changes. This theoretical work is proposed to predict the adsorption and sensing potential of various Ti₂C nanosheets towards ethylbenzene (a kind of gas marker for lung cancer) and would help to guide experimentalists to develop better Ti₂C-based 2-D materials for gas detection applications in the future.