Elevated Energy Levels Research Articles

Computational studies on the catalytic potential of the double active site for enzyme engineering

Proteins possessing double active sites have the potential to revolutionise enzyme design strategies. This study extensively explored an enzyme that contains both a natural active site (NAS) and an engineered active site (EAS), focusing on understanding its structural and functional properties. Metadynamics simulations were employed to investigate how substrates interacted with their respective active sites. The results revealed that both the NAS and EAS exhibited similar minimum energy states, indicating comparable binding affinities. However, it became apparent that the EAS had a weaker binding site for the substrate due to its smaller pocket and constrained conformation. Interestingly, the EAS also displayed dynamic behaviour, with the substrate observed to move outside the pocket, suggesting the possibility of substrate translocation. To gain further insights, steered molecular dynamics (SMD) simulations were conducted to study the conformational changes of the substrate and its interactions with catalytic residues. Notably, the substrate adopted distinct conformations, including near-attack conformations, in both the EAS and NAS. Nevertheless, the NAS demonstrated superior binding minima for the substrate compared to the EAS, reinforcing the observation that the engineered active site was less favourable for substrate binding due to its limitations. The QM/MM (Quantum mechanics and molecular mechanics) analyses highlight the energy disparity between NAS and EAS. Specifically, EAS exhibited elevated energy levels due to its engineered active site being located on the surface. This positioning exposes the substrate to solvents and water molecules, adding to the energy challenge. Consequently, the engineered enzyme did not provide a significant advantage in substrate binding over the single active site protein. Further, the investigation of internal channels and tunnels within the protein shed light on the pathways facilitating transport between the two active sites. By unravelling the complex dynamics and functional characteristics of this double-active site protein, this study offers valuable insights into novel strategies of enzyme engineering. These findings establish a solid foundation for future research endeavours aimed at harnessing the potential of double-active site proteins in diverse biotechnological applications.

Stabilizing atomic Ru species in conjugated sp2 carbon-linked covalent organic framework for acidic water oxidation

Suppressing the kinetically favorable lattice oxygen oxidation mechanism pathway and triggering the adsorbate evolution mechanism pathway at the expense of activity are the state-of-the-art strategies for Ru-based electrocatalysts toward acidic water oxidation. Herein, atomically dispersed Ru species are anchored into an acidic stable vinyl-linked 2D covalent organic framework with unique crossed π-conjugation, termed as COF-205-Ru. The crossed π-conjugated structure of COF-205-Ru not only suppresses the dissolution of Ru through strong Ru-N motifs, but also reduces the oxidation state of Ru by multiple π-conjugations, thereby activating the oxygen coordinated to Ru and stabilizing the oxygen vacancies during oxygen evolution process. Experimental results including X-ray absorption spectroscopy, in situ Raman spectroscopy, in situ powder X-ray diffraction patterns, and theoretical calculations unveil the activated oxygen with elevated energy level of O 2p band, decreased oxygen vacancy formation energy, promoted electrochemical stability, and significantly reduced energy barrier of potential determining step for acidic water oxidation. Consequently, the obtained COF-205-Ru displays a high mass activity with 2659.3 A g−1, which is 32-fold higher than the commercial RuO2, and retains long-term durability of over 280 h. This work provides a strategy to simultaneously promote the stability and activity of Ru-based catalysts for acidic water oxidation.

Identification of rare earth elements in synthetic and natural monazite and xenotime by visible-to-shortwave infrared reflectance spectroscopy

To support the role of proximal and remote sensing in geological rare earth element (REE) resource exploration, we studied the reflectance spectroscopy of synthetic single- and mixed-REE phosphate phases. Synthesis yielded monazite for the elements La to Gd, and xenotime for Dy to Lu and Y. Visible-to-shortwave infrared (350–2500 nm) reflectance spectra of synthetic single-REE monazites and xenotimes can be used to identify the ions responsible for the absorption features in natural monazites and xenotimes. Nd3+, Pr3+ and Sm3+ produce the main absorption features in monazites. In natural xenotime, Dy3+, Er3+, Ho3+ and Tb3+ ions cause the prevalent absorptions. The majority of the REE-related absorption features are due to photons exciting electrons within the 4f subshell of the trivalent lanthanide ions to elevated energy levels resulting from spin-orbit coupling. There are small (< 20 nm) shifts in the wavelengths of these absorptions depending on the nature of the ligands. The energy levels are further split by crystal field effects, manifested in the reflectance spectra as closely spaced (∼ 5–20 nm) multiplets within the larger absorption features. Superimposed on the electronic absorptions are vibrational absorptions in the H2O molecule or within [OH]−, [CO3]2− and [PO4]3− functional groups, but so far only the carbonate-related spectral features seem usable as a diagnostic tool in REE-bearing minerals. Altogether, our study creates a strengthened knowledge base for detection of REE using reflectance spectroscopy and provides a starting point for the identification of REE and their host minerals in mineral resources by means of hyperspectral methods.

Thermodynamics and energy properties of the lowest eutectic mixture of TNBA/MTNP

In light of the challenges posed by the low density, diminished energy levels, and shrinkage holes in the loading arise of the current cast-cured explosive liquid vehicle, TNT, the investigation of low-melting eutectic materials as potential substitutes for TNT has emerged as a focal point of research. By employing the solvent-nonsolvent method, the lowest eutectic mixture of TNBA(2,4,6-trinitro-3-bromoanisole)/MTNP(1-methyl-3,4,5-trinitropyrazole) was synthesized, distinguished by a moderate melting point and markedly elevated energy levels as compared to TNT. Comprehensive SEM, EDS, IR, XRD, and XPS analyses were conducted on the lowest eutectic mixture, substantiating the absence of any chemical interaction between TNBA and MTNP and affirming their exceptional compatibility. Moreover, an exploration into the thermal decomposition behavior and mechanism of the lowest eutectic mixture was undertaken, its mechanical sensitivity was tested, and its detonation performance was evaluated by EXPLO-5 software. The thermal decomposition parameters of the lowest eutectic mixture closely paralleled those of the precursor materials, with the thermal decomposition kinetics model function being identified as the Jander function. The impact sensitivity of the lowest eutectic was 48.1 cm and the friction sensitivity was 12%. Furthermore, the density of the lowest eutectic mixture surpassed 1.8 g/cm3, and its detonation velocity approached 8000 m/s, markedly surpassing the explosive performance of TNT.

Optimization of Carbon-Defect Engineering to Boost Catalytic Ozonation Efficiency of Single Fe─N4 Coordination Motif.

Carbon-defect engineering in single-atom metal-nitrogen-carbon (M─N─C) catalysts by straightforward and robust strategy, enhancing their catalytic activity for volatile organic compounds, and uncovering the carbon vacancy-catalytic activity relationship are meaningful but challenging. In this study, an iron-nitrogen-carbon (Fe─N─C) catalyst is intentionally designed through a carbon-thermal-diffusion strategy, exposing extensively the carbon-defective Fe─N4 sites within a micro-mesoporous carbon matrix. The optimization of Fe─N4 sites results in exceptional catalytic ozonation efficiency, surpassing that of intact Fe─N4 sites and commercial MnO2 by 10 and 312 times, respectively. Theoretical calculations and experimental data demonstrated that carbon-defect engineering induces selective cleavage of C─N bond neighboring the Fe─N4 motif. This induces an increase in non-uniform charges and Fermi density, leading to elevated energy levels at the center of Fe d-band. Compared to the intact atomic configuration, carbon-defective Fe─N4 site is more activated to strengthen the interaction with O3 and weaken the O─O bond, thereby reducing the barriers for highly active surface atomic oxygen (*O/*OO), ultimately achieving efficient oxidation of CH3SH and its intermediates. This research not only offers a viable approach to enhance the catalytic ozonation activity of M─N─C but also advances the fundamental comprehension of how periphery carbon environment influences the characteristics and efficacy of M─N4 sites.

Mechanistic insights into the AIE properties of BF2 complexes of N-acetyl 2-aminobenzothiazoles as rotorless polyheteroaromatics

A series of four novel BF2 complexes of N-acetyl 2-aminobenzothiazoles featuring rigid rotorless polyheteroaromatic structures have been designed and synthesized. All of these compounds exhibited AIE properties with excellent solid-state fluorescence quantum yields up to 81.7%. Theoretical calculations revealed the characteristics of their ground-state structures and excitation processes. Their seemingly abnormal nonradiative decay in solutions was investigated from both direct vibrational relaxation and S0/S1 surface crossing perspectives by the two-channel model. The minimum energy conical intersection (MECI) located by SF-TDDFT method indicated that the CI is mainly induced by the deformation of the BF2 complex ring, leads to elevated energy level, and thus is not responsible for the fluorescence quenching. The potential energy curve (PEC) constructed along the distortion angle θ of BF2 complex ring showed that when θ reaches 50° (the dark-state region approaching MECI), the energy barrier is only 0.11 eV, suggesting that the deformed dark state could serve as an effective deactivation channel via ultrafast internal conversion (IC). Crystallographic analysis illustrated that the F atoms perpendicular to the polyheterocycle could effectively prohibit detrimental π-π stacking and enhance intermolecular interactions, thereby resulting in efficient solid-state emission.

Insight into the structural, elastic, phonon dispersions, and optoelectronic properties of Cs2YXCl6 (X = In, Tl) double perovskites for solar cells and energy conversion applications

Due to their lack of lead, stability, and outstanding performance, double perovskites have emerged as a prominent subject of study in solar cell research. Thus, we present an analysis of the structural, elastic, electronic, and optical characteristics of Cs2YXCl6 (X = In, Tl) with regard to their applications in solar cells and thermoelectric generators. The structural stability has been validated by observing the thermodynamic stability, as evidenced by the negative formation energy and the fitting of the Birch-Murnaghan equation of state. The confirmation of structural stability in our materials is further supported by the absence of imaginary frequencies in the phonon dispersion calculations. The mechanical stability of both compounds is established by the relationship between their elastic constants, specifically C11 - C12 > 0, C11 > 0, C11 + 2 C12 > 0, and B > 0. However, it should be noted that these materials are characterized as mechanically anisotropic and ductile. By employing the highly promising Tb-MBj potential, the band gaps of Cs2YInCl6 and Cs2YTlCl6 have been calculated to be 4 eV and 0.9 eV, respectively. Cs2YInCl6 is categorized as an insulator, whereas Cs2YTlCl6 is considered a semiconductor. This distinction arises from the higher atomic mass of Tl in comparison to In, which results in elevated energy levels within the conduction band. A comprehensive investigation of the optical properties of both compounds was conducted within the energy range of 0 eV to 40 eV. It was found that these compounds exhibit significant absorption and optical conductivity in the higher energy range. Conversely, they demonstrate transparency to incident photons in the lower energy range. Based on our analysis of the optical properties, we have determined that these compounds are well-suited for applications in high-frequency UV devices. To the best of our knowledge, this study represents the first comprehensive theoretical analysis of the structural, elastic, electronic, and optical properties of Cs2YXCl6 (X = In and Tl), which have not yet been experimentally confirmed. In Summary, Cs2YXCl6 (X = In, Tl) exhibits significant promise for both solar cell and thermoelectric applications, showcasing its potential to contribute to the advancement of renewable energy and efficient energy conversion technologies.

Clinical Aspect of Injury-Related Radiation Exposure

Radiation exposure can occur due to a multitude of sources, such as environmental variables, occupational activities, medical treatments, inadvertent accidents, or deliberate actions. The purpose of this review was to provide a detailed analysis of the clinical aspects associated with radiation exposure resulting from injuries. Both non-ionizing and ionizing sources emit radiation. Nonionizing radiation pertains to radiation characterized by low energy levels, which might induce injuries associated with localized thermal harm. Nonionizing radiation encompasses several forms of electromagnetic radiation, such as microwaves, ultraviolet light, visible light, and radio waves. Ionizing radiation is distinguished by its elevated energy levels, which lead to numerous harmful effects on the human body. The main focus of the treatment is decontamination, relieving symptoms, providing supportive care, and offering psychosocial aid. Additionally, it also involves managing any coexisting diseases or injuries. Personalized supportive care is tailored based on the specific dosage, route of administration, and outcomes of exposure, as well as any concurrent conditions. In conclusion, the intensity of radiation damage is influenced by various factors such as the origin, kind, amount, duration, location, susceptibility of individuals, and the overall cumulative exposure.

Conformation Flipping of Asymmetric Nonfullerene Acceptors Enabling High‐Performance Organic Solar Cells with 77% Fill Factors

Considerable progress on high‐performance organic solar cells (OSCs) has been achieved in the past due to the rapid development of nonfullerene acceptors (NFAs). Typically, two kinds of methods have been employed to manipulate energy levels and aggregation of NFAs, i.e., molecular engineering on alkyl side chains and modification of the heterocyclic rings in the backbone. Herein, a novel asymmetric thiophene[3,2‐b] pyrrole (TP)‐based NFA with flipped molecular conformation, named as PTBTT‐4F, is designed and synthesized. The introduction of the pyrrole ring in the novel NFA would not only afford extra reaction sites for side chain modification, but also induce substantial intramolecular charge transfer, thus leading to elevated energy levels of the NFA and thereby lower energy loss of the OSCs. When pairing with polymer donor PBDB‐TF to fabricate OSCs, concurrent improvement in open‐circuit voltage, short‐circuit current (JSC), and fill factor (FF) is realized, which delivers an outstanding power conversion efficiency (PCE) of 14.49%. Benefitting from effective molecular stacking and optimized phase separation induced by molecular conformation variation, asymmetric PTBTT‐4F fabricated OSCs exhibit much higher JSCs and FFs than the symmetrical PTBTP‐4F devices.

Efficient Combination of Carbon Quantum Dots and BiVO4 for Significantly Enhanced Photocatalytic Activities

The development of highly efficient and stable photocatalysts is of critical importance for the removal of environmental pollutants, such as paraben preservatives. In this work, carbon quantum dots (CQDs) were used to modify bismuth vanadate (BiVO4) through a hydrothermal reaction. Regarding the as-formed CQDs/BiVO4 composite, TEM, XPS, and Raman spectra analysis demonstrated the strong interaction between CQDs and BiVO4, possibly leading to the elevated energy level of the composite. As compared to pristine BiVO4, CQDs/BiVO4 showed an increase in light harvesting, and significantly enhanced visible-light activities in degrading the typical paraben pollutant—benzyl paraben (BzP)—where the maximum 85.4% of BzP was degraded in 150 min. After four cycle reactions, the optimum sample 0.6%CQDs/BiVO4 still degraded 78.2% of BzP, indicating the good stability and reusability of the composite. The notably higher photocurrent and smaller arc in Nyquist plot were measured by CQDs/BiVO4, unveiling the improved photocharge separation and lowered interfacial charge transfer resistance by CQDs modification. Meanwhile, due to the promoted energy level, CQDs/BiVO4 practically produced •O2− species and thereby contributed to the BzP degradation, while they had no ability to produce •OH. This was contrary to the BiVO4 system, where •OH and h+ played the dominant roles.

Enhancing Triplet-Triplet Annihilation Upconversion: From Molecular Design to Present Applications.

Photon upconversion, the process of converting low-energy photons into high-energy ones, has been widely applied for solar energy conversion, photoredox catalysis, and various biological applications such as background-free bioimaging, cancer therapy, and optogenetics. Upconversion materials that are based on triplet-triplet annihilation (TTA) are of particular interest due to their low excitation power requirements (e.g., ambient sunlight) and easily tunable excitation and emission wavelengths. Despite advances that have been made with respect to TTA upconversion (TTA-UC) in the past decade, several challenges remain for near-infrared light-activatable triplet-triplet annihilation upconversion (NIR TTA-UC). These challenges include low upconversion quantum yield, small anti-Stokes shift, and incompatibility with oxygen, the latter of which seriously limits the practical applications of NIR TTA-UC.This Account will summarize the recent research endeavors to address the above-mentioned challenges and the recent new applications. The first part of this Account highlights recent strategies of molecular design to modulate the excited states of photosensitizers and annihilators, two key factors to determine TTA-UC performance. Novel molecular engineering strategies such as the resonance energy transfer method, dimerization of dye units, and the helix twist molecular structure have been proposed to tune the excited states of photosensitizers. The obtained photosensitizers exhibited enhanced absorption of deep tissue penetrable near-infrared (NIR) light, produced a triplet excited state with elevated energy level and prolonged lifetime, and promoted intersystem crossing, leading to an upgraded TTA-UC system with significantly expanded anti-Stokes shift. With respect to the annihilator, the perylene derivatives were systematically explored, and their attached aromatic groups were found to be the key to adjusting the energy levels of both the triplet and singlet excited states. The resultant optimal TTA-UC system exhibits the highest recorded efficiency among NIR TTA-UC systems.Moreover, to resolve the oxygen-induced TTA-UC quenching, enzymatic reactions were recently introduced. More specifically, the glucose oxidase-catalyzed glucose oxidation reaction showed the ability to rapidly consume oxygen to turn on the TTA-UC luminescence in an aqueous solution. The resultant TTA-UC nanoparticle was able to detect glucose and an enzyme related to glucose metabolism in a highly specific, sensitive, and background-free manner. Further, the upconverted singlet excited state of the annihilator was directly utilized as the catalyst or the excited substrate. For example, the modification of annihilators and drug molecules with photolabile linkages can realize the long wavelength light-induced photolysis. Compared to direct short-wavelength-driven photolysis, this sensitized TTA photolysis (TTAP) exhibits superior reaction yield and lower photodamage, which are important in the release of drugs for tumor treatment in vivo. Moreover, the improved upconversion efficiency can enable the successful coupling of NIR TTA-UC with a visible light absorbing photocatalyst for NIR-driven photoredox catalysis. Compared to direct visible-light photocatalysis, TTA-UC mediated NIR photoredox catalysis showed superior product yield especially in large scale reaction systems owing to the deep penetration power of NIR light. More interestingly, among a few promising technology applications, three-dimensional (3D) printing based on photopolymerization can operate with faster speed and energy-input several orders of magnitude lower when the two-photon polymerization is replaced with TTA-UC mediated polymerization. We believe this Account will spur interest in the further development and application of TTA-UC in the areas of energy, chemistry, material science, and biology.

Cis‐Trans Isomerism Inducing Cocrystal Polymorphism with Thermally Activated Delayed Fluorescence and Two‐Photon Absorption

AbstractThe cocrystals of 2‐(benzo[d]thiazol‐2‐yl)‐3‐(pyren‐1‐yl)acrylonitrile (Py‐BZTCN) and 1,2,4,5‐tetracyanobenzene (TCNB) are constructed through intermolecular charge‐transfer (CT) interactions between donor and acceptor. Cis‐ and trans‐isomers of Py‐BZTCN induce the formation of two different crystal packing with 1:2 and 1:1 stoichiometric ratios between Py‐BZTCN and TCNB, corresponding to the cocrystals of PCNTC‐O and PCNTC‐R, respectively. PCNTC‐O cocrystal exhibits orange‐yellow normal fluorescence with a CT from pyrene (Py) monomer to TCNB, while PCNTC‐R cocrystal presents red thermally activated delayed fluorescence (TADF) with a CT from Py dimer to TCNB. This photophysical difference originates from that, relative to Py monomer, Py dimer has an elevated energy level of highest occupied molecular orbital (HOMO), which results in a stronger CT in PCNTC‐R cocrystal. Both cocrystals possess unique two‐photon absorption (TPA) properties, and changing monomer into dimer as a donor in the CT cocrystal effectively alters the supramolecular properties. Noteworthily, PCNTC‐R is a rare case in which TADF and TPA are integrated into a cocrystal, opening up a new supramolecular strategy to explore the multi‐functional materials.

In Silico Studies of Two Biphenyl Based Oxime Containing Ligands

Two biphenyl based ligands were tested for their molecular docking, ADME and toxicity properties in silico. Molecular docking studies performed with two factors (VEGFR-2 and EGFRK) which are known to be effective in tumor growth. Two ligands were similar in structure except one atom difference between ligands which is H and Cl. This small difference made an important impact on the molecular docking energy scores of ligand protein couples. The Cl atom containing ligand-protein complexes showed drastically elevated energy levels which might be due to higher electronegativity of Cl atom. ADME properties of two ligands were also alike except a few parameters as the inhibition of two conjugation enzymes (CYP2C19 ve CYP2C9). The biggest difference shown by the ligands were the elimination of carcinogenicity and mutagenicity of H containing ligand by Cl atom containing ligand. Druglikeness of two biphenyl based oxime containing ligands was also tested and the results of a single atom exchange were evaluated in terms of new drug design and discovery.

Theoretical design study on the origin of the improved phosphorescent efficiency of DPEphos quinoline-substituted derivatives for OLEDs

Various tetrahedral heteroleptic Cu(I) complexes, as red organic light-emitting diodes (OLEDs), show a concern of maximizing the quantum yield (QY) in order to improve the optoelectronic performance. Herein, three experimental [Cu(N^N) (bis [2-(diphenylphosphino)phenyl]ether)]+ (named 1, 2 and 3) were selected as the jumping-off point, following two complexes (named 4 and 5) were successfully designed by introducing bulky electron-donating substituents into N^N ligands continuously. As expected, the QY of designed complexes 4 (0.26) and 5 (0.13) exhibit over twice higher than that of 3 (5.4 × 10−2). This can be attributed to the enhanced electron-donating property of N^N ligand, which accelerated the radiative transition rate (kr) through the apparently elevated energy level of the lowest triplet excited state (T1) and strengthened transition dipole moments, even though the spin-orbit coupling (SOC) effect is weakened. Simultaneously, the tetrahedral geometric distortion could be effectively restrained by the bulky N^N ligands, but the high vibrational freedom of the terminal substituents could also bring in some unfavorable intra-ligand deformation, resulting in an upward of the nonradiative transition rate (knr) at 5 (knr: 0.30 × 105 s−1 for 4; 0.95 × 105 s−1 for 5). Therefore, it's worth noting that the balance of excited state energy level, SOC effect as well as the reorganization energy ought to be elaborately regulated to achieve the optimal QY. This detailed investigation on the microscopic mechanism of these Cu(I) complexes can provide instructive inspiration for experimentalists.

Enhanced Photodetection Performance in Graphene-Assisted Tunneling Photodetector

The vertical van der Waals heterostructures based on 2-D materials have attracted tremendous attention in optoelectronic devices as they can offer perfect interface without dangling bonds, atomic layer thicknesses, and conveniently tunable energy band alignment. However, the carrier transport mechanism in vertically stacked van der Waals heterostructure photodetectors is usually neglected in regards of photoresponse enhancement strategy, leading to low photoresponsivity and quantum efficiency. Here, we report a vertically stacked tunneling photodetector based on WSe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /graphene/WS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> van der Waals heterostructure. By introducing graphene film into the WSe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /WS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> interface, the interface composition was ameliorated and the Fowler–Nordheim tunneling (FNT) was enhanced with the reduced tunneling barrier height and thickness, caused by the elevated energy level of electrons since strong electron–electron interaction, ultrafast thermalization (~50 fs), and massless Dirac electrons of graphene. Therefore, the device exhibits a high photocurrent/dark current ratio (>10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> ), fast response time ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 300~ \mu \text{s}$ </tex-math></inline-formula> ), high detectivity ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 1.58\times 10^{12}$ </tex-math></inline-formula> Jones), and high responsivity (429 mA W <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> ) across a broad spectral range till <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1~ \mu \text{m}$ </tex-math></inline-formula> at room temperature. The optimized detectivity and responsivity are about 150 times and 50 times higher than WSe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /WS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> device without graphene, respectively. These results contribute to offer a novel and versatile strategy for overcoming the performance limitation in van der Waals photodetector.

Structural, mechanical, optoelectronic and thermoelectric properties of double perovskite compounds Cs2TeX6 (X = Br, I) for energy storage applications: First principles investigations

First principles calculations were performed to investigate the structural, mechanical, optoelectronic and thermoelectric properties of double perovskite Cs2TeX6 (X = Br, I) compounds in the cubic structure using the full potential linearized augmented plane wave method. The main results are founded as follows: (1) Calculations reveal the indirect band gap for the two materials; our results are in agreement with the available experimental and theoretical data. (2) The elastic constants Cij's indicate that the cubic phase is mechanically stable and reveal ductility behavior. (3) The real and imaginary parts of dielectric function for the cubic phases for both compounds demonstrate an optical band gap similar to the electronic one and a substantial absorption in the ultraviolet region of the spectrum in elevated energy level. (4) Thermoelectric properties are reported as a function of temperature ensuring a beneficial trend of these materials in energy storage applications.

A new investigation of Ruddlesden-Popper compounds Ba2MO4 (M = Sn, Pb) through structural, elastic, electronic, optical and thermoelectric properties

First principles calculations were performed to investigate the structural, electronic, elastic, optical and thermoelectric properties of Ruddlesden-Popper (RP) Ba2MO4 (M ​= ​Sn, Pb) compounds in the tetragonal structure using the full potential linearized augmented plane wave method. The main results are found as follows: (1) the two compounds are semiconductors having indirect band gaps, our results are in agreement with the available experimental and theoretical data. (2) The elastic constants Cij indicate that the tetragonal phase is mechanically stable. (3) The real and imaginary parts of dielectric function for the tetragonal phases for both compounds demonstrate an optical band gap similar to the electronic one and a substantial absorption in the ultraviolet region of the spectrum in elevated energy level. (4) Thermoelectric properties are reported as a function of temperature ensuring a beneficial trend of these materials in energy storage applications.

Locating mental toughness in factor models of personality

We examined the degree to which two factor models of personality capture mental toughness. We focused on item and facet-level correlates of mental toughness in three widely used personality inventories – HEXACO and Hogan Personality Inventory (bright side personality) and Hogan Development Survey (dark side personality). US-based college students and NCAA athletes (Sample 1; N = 285) and working adults (Sample 2; N = 218) took the Sports Mental Toughness Questionnaire and the HEXACO-60 (Sample 1) and the HPI and HDS (Sample 2). We used lasso regression with cross-validation to identify the HEXACO-60's items and HPI and HDS' facets predicting mental toughness. In Study 1 the strongest predictors of mental toughness were 12 items coming from the eXtraversion, Emotionality, and Conscientiousness scales. Item content examinations indicated that people scoring high on mental toughness tended to endorse items related to pushing for results, having elevated energy levels, and a high degree of self-confidence. In Study 2, emotional control, ambition, self-efficacy, creativity, and low anxiety emerged as the strongest facet correlates of mental toughness. Mental toughness is located between factors of the HEXACO model, but much more squarely aligned with Ambition in the HPI inventory.

Isatin-derived non-fullerene acceptors towards high open circuit voltage solar cells

Two new non-fullerene acceptors (NFAs) have been synthesized for organic solar cell (OSC) applications. Isatin related weak electron withdrawing moieties were coupled with indacenodithiophene to give new NFAs with elevated energy levels, especially the LUMO levels. The NFAs were designed to pair with wide band-gap donor polymers for reducing energy loss (Eloss) and therefore achieving high open circuit voltages (Voc) in organic solar cells. The OSC devices with the new NFAs as acceptors showed the Voc as high as 1.18 V. The high open circuit voltages were achieved via small Eloss.

Nonfullerene Acceptors with Enhanced Solubility and Ordered Packing for High-Efficiency Polymer Solar Cells

The performance of polymer solar cells (PSCs) is commonly improved using additives or annealing treatment. However, these processes are accompanied by disadvantages, including poor reproducibility and stability. Herein, a molecular design strategy is proposed to obtain additive- and annealing-free PSCs. IDTOT2F containing two alkoxyl side chains at the central unit of the nonfullerene acceptor IDTT2F was developed. This molecular design results in excellent solubility in solutions, ordered molecular packing in films, slightly elevated energy levels, and a higher film absorption coefficient. Compared with its counterpart IDTT2F, its improved solubility provides an active layer with better morphology, its ordered molecular packing enhances the charge mobility in blend films, and its slightly elevated energy level furnishes a higher open-circuit voltage of devices. As a result, IDTOT2F-based devices display a maximum power conversion efficiency of 12.79%, which is one of the highest values reported for a PSC...