Conducted Density Functional Theory Research Articles

Fermi energy modulation by tellurium doping of thermoelectric copper(I) iodide

Copper(I) iodide (CuI) is the leading inorganic p-type transparent conductor, attracting major attention for its promising optoelectronic properties and facile growth methods, although, commercial uptake is limited due to its as-of-yet insufficient electrical conductivity. Doping CuI with the chalcogens (O, S, Se, Te) is a viable route to tune its electrical conductivity for applications such as in thin film transistors, hole transport layers in solar cells, and transparent thermoelectric generators. The heaviest chalcogen element, Te, is yet to be explored in heavily intrinsically p-type doped CuI at non-alloying concentrations, the subject of the present work. We report the effects of tellurium at the boundary between the doping and alloying regime (up to a maximum of 2.4 % Te) in CuI thin films and investigation the variation in the thermoelectric properties and electronic band structure of the material. Ion implanting tellurium into CuI led to a progressive reduction in the films' work functions from 4.9 eV to 4.5 eV while the ionization potential remained unchanged, measured through photoemission spectrometry. This signified a modulation of the Fermi energy relative to the valence band edge, having a major effect on the materials' electrical conductivity and Seebeck coefficient, the former decreasing by 3 orders of magnitude, while the latter increased by 80 %. We conducted density functional theory (DFT) calculations to elucidate the effect of tellurium doping on the band structure of CuI. Tellurium doping corroborated the shift of Fermi energy, the incorporation of impurity acceptor states deeper into the band gap, in addition to disordering the valence band maximum. This work shows that, the Fermi energy in heavily p-type doped CuI can be moved away from the valence band through Te doping in addition to introducing band disorder, useful for controlling the hosts’ transport properties.

Mechanistic Insights into Oxidation of Benzaldehyde by Co-Peroxo Complexes.

Transition metal-peroxide complexes play a crucial role as intermediates in oxidation reactions. To unravel the mechanism of benzaldehyde oxidation by the Co-peroxo complex, we conducted density functional theory (DFT) calculations. The identified competing mechanisms include nucleophilic attack and hydrogen atom transfer (HAT). The nucleophilic attack pathway involves Co-O cleavage and nucleophilic attack, leading to the formation of the benzoate product. And the HAT pathway comprises O-O cleavage and HAT, ultimately resulting in the benzoate product. DFT calculations revealed that the formation of the end-on Co-superoxo complex 2 through Co-O cleavage, starting from the side-on Co-peroxo complex 1, is much more favorable than the formation of the two-terminal oxyl-radical intermediate 3 through O-O cleavage. Compared with the nucleophilic attack of benzaldehyde by 2, the abstraction of a hydrogen atom from benzaldehyde by 3 requires higher energy. The nature of the nucleophilicity of 2 and 3 accounts for the reactivity of the reaction.

Tailoring hydrogen storage performance in γ-graphyne through valence band modulation of adsorbed Li via doping and strain

Hydrogen storage is indeed fundamental to utilizing H2 effectively, and porous carbon materials have emerged as highly promising supports for this purpose. γ-Graphyne (γGy) possesses abundant chemical bonds, considerable porosity, and exceptional chemical stability, positioning it as a promising candidate for hydrogen storage and transport applications. In this study, we conducted density functional theory calculations to investigate the potential of Li- and Na-loaded γGy as hydrogen storage materials. Our findings reveal that the hydrogen storage capacity (HSC) of Na-loaded γGy falls significantly short of expectations, whereas Li-loaded γGy demonstrates a notably higher HSC. Subsequently, our calculations indicate that B-doping of γGy does not promote favorable HSC, whereas N-doping exhibits a beneficial effect. Furthermore, we observed that tensile strain favors the hydrogen storage properties of 4Li@γGy and 4Li@N-γGy, while compressive strain enhances the hydrogen storage characteristics of 4Li@B-γGy. Notably, we discovered the capacity to adjust the valence band center of Li (ɛVB), consequently influencing the hydrogen storage performance of γGy. Our investigation suggests that increased overlap between ɛVB in Li-loaded graphyne and the effective alignment of H2 and the supporting structure augments the binding force between Li and H2, thereby amplifying the HSC.

Contact‐Electro‐Catalysis for Direct Oxidation of Methane under Ambient Conditions

AbstractThe conversion of methane under ambient conditions has attracted significant attention. Although advancements have been made using active oxygen species from photo‐ and electro‐ chemical processes, challenges such as complex catalyst design, costly oxidants, and unwanted byproducts remain. This study exploits the concept of contact‐electro‐catalysis, initiating chemical reactions through charge exchange at a solid–liquid interface, to report a novel process for directly converting methane under ambient conditions. Utilizing the electrification of commercially available Fluorinated Ethylene Propylene (FEP) with water under ultrasound, we demonstrate how this interaction promote the activation of methane and oxygen molecules. Our results show that the yield of HCHO and CH3OH can reach 467.5 and 151.2 μmol ⋅ gcat−1, respectively. We utilized electron paramagnetic resonance (EPR) to confirm the evolution of hydroxyl radicals (⋅OH) and superoxide radicals (⋅OOH). Isotope mass spectrometry (MS) was employed to analyze the elemental origin of CH3OH, which can be further oxidized to HCHO. Additionally, we conducted density functional theory (DFT) simulations to assess the reaction energies of FEP with H2O, O2, and CH4 under these conditions. The implications of this methodology, with its potential applicability to a wider array of gas‐phase catalytic reactions, underscore a significant advance in catalysis.

Contact-Electro-Catalysis for Direct Oxidation of Methane under Ambient Conditions.

The conversion of methane under ambient conditions has attracted significant attention. Although advancements have been made using active oxygen species from photo- and electro- chemical processes, challenges such as complex catalyst design, costly oxidants, and unwanted byproducts remain. This study exploits the concept of contact-electro-catalysis, initiating chemical reactions through charge exchange at a solid-liquid interface, to report a novel process for directly converting methane under ambient conditions. Utilizing the electrification of commercially available Fluorinated Ethylene Propylene (FEP) with water under ultrasound, we demonstrate how this interaction promote the activation of methane and oxygen molecules. Our results show that the yield of HCHO and CH3OH can reach 467.5 and 151.2 μmol ⋅ gcat -1, respectively. We utilized electron paramagnetic resonance (EPR) to confirm the evolution of hydroxyl radicals (⋅OH) and superoxide radicals (⋅OOH). Isotope mass spectrometry (MS) was employed to analyze the elemental origin of CH3OH, which can be further oxidized to HCHO. Additionally, we conducted density functional theory (DFT) simulations to assess the reaction energies of FEP with H2O, O2, and CH4 under these conditions. The implications of this methodology, with its potential applicability to a wider array of gas-phase catalytic reactions, underscore a significant advance in catalysis.

Study on the Sodium-Doped Titania Interface-Type Memristor.

Memristors integrated into a crossbar-array architecture (CAA) are promising candidates for analog in-memory computing accelerators. However, the relatively low reliability of the memristor device and sneak current issues in CAA remain the main obstacles. Alkali ion-based interface-type memristors are promising solutions for implementing highly reliable memristor devices and neuromorphic hardware. This interface-type device benefits from self-rectifying and forming-free resistive switching (RS), and exhibits relatively low variation from device to device and cycle to cycle. In a previous report, we introduced an in situ grown Na/TiO2 memristor using atomic layer deposition (ALD) and proposed a RS mechanism from experimentally measured Schottky barrier modulation. Self-rectifying RS characteristics were observed by the asymmetric distribution of Na dopants and oxygen vacancies as the Ti metal used as the adhesion layer for the bottom electrode diffuses over the Pt electrode at 250 °C during the ALD process and is doped into the TiO2 layer. Here, we theoretically verify the modulation of the Schottky barrier at the TiO2/Pt electrode interface by Na ions. This study fabricated a Pt/Na/TiO2/Pt memristor device and confirmed its self-rectifying RS characteristics and stable retention characteristics for 24 h at 85 °C. Additionally, this device exhibited relative standard deviations of 27 and 7% in the high and low resistance states, respectively, in terms of cycle-to-cycle variation. To verify the RS mechanism, we conducted density functional theory simulations to analyze the impact of Na cations at interstitial sites on the Schottky barrier. Our findings can contribute to both fundamental understanding and the design of high-performance memristor devices for neuromorphic computing.

Efficient crystal structure materials as reactive sorbent for the CO2 and CH4 adsorption and storage

The efficient dirubidium cobalt bis(dihydrogendiphosphate) dihydrate compound is successfully synthesized in a solution and used as a reactive sorbent for the CO2 and CH4 gases adsorption and storage. A crystal of this Rb2Co(H2P2O7)2·2H2O compound has been isolated and characterized by single X-ray diffraction analysis and was found to crystallize in the triclinic system (P1¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$P\\overline{1}$$\\end{document}) with the cell parameters (Å): 6.980(1), 7.370(1), 7.816(1), 81.74(1), 70.35(1), 86.34(1); V = 374.68(9) Å3, Z = 2. The crystal-packing consists of a three-dimensional framework made upon corners and edges sharing of [RbO7], [H2P2O7] and [CoO6] entities, furthermore linked by a network of H-bonds. The UV–Vis spectroscopy revealed usual transitions between the ground state 4T1g and the upper levels 4T2g, 4A2g and 4T1g (P). Moreover, the CO2 and CH4 gases sorption measurements were successfully performed at two different temperatures (25 and 45 °C) and various pressures ranging from vacuum to 50 bar. Our results show that rate of CO2 and CH4 capturing was 3.10 mmol/g and 2.35 mmol/g at temperature 25 °C and pressure 50 bar, respectively. This compound showed a clear potential for CO2/CH4 adsorption and storage thereby paving the way towards its exploration and adaptation for capturing and collecting carbon dioxide and greenhouse gases from the air, and their conversion into hydrocarbon fuels using existing mature technologies. We have also conducted density functional theory calculations to study the CO2 and CH4 adsorption properties of Rb2Co(H2P2O7)2·2H2O. The simulation results show enhanced adsorption of both types of molecules on the surface of the material.

Molecular engineering of D-π-A-type structures based on nitrobenzofurazan (NBD) derivatives for both organic solar cells and nonlinear optical response

The electronic, photo-physical, and nonlinear optical (NLO) properties of small molecules from nitrobenzofurazan (NBD) derivatives have been fine-tuned through the introduction of various electron-donating groups (OH, OCH3, and N(CH3)2). These designed small molecules follow a donor-linker-acceptor (D-π-A) motif, featuring p-phenylene as the electron donor, thiophene as the π-conjugated bridge, and NBD as the electron acceptor. To achieve this, we conducted density functional theory (DFT) and its time-dependent counterpart, TD-DFT calculations. Our exploration of the structure–property relations among the molecular parameters revealed that the introduction of donor groups has a notable influence on lowering the highest occupied molecular orbital (HOMO) energy levels. Analysis of the absorption–emission spectra showed a prominent π → π* band followed by a weaker n → π* band.Remarkably, three compounds substituted with electron-donor group’s exhibit anti-Stokes fluorescence (ASF) emission. Moreover, the relatively weak emission band associated with the charge transfer n → π* transition of the nitro-functionalized molecules is quenched, similar to the π → π* electronic transition. Consequently, these compounds display a lower bandgap energy, resulting in a broad optical absorption profile with emissions spanning from green to yellow. Notably, when tuning the NLO properties, push-type groups exhibit demonstrate exceptionally high hyperpolarizabilities. Furthermore, our investigation unveiled excellent photovoltaic properties, with these compounds achieving an impressive power conversion efficiency (PCE) of approximately 7 %.Additionally, we conducted complementary topological analyses, including Molecular Electrostatic Potential (MEP), Quantum Theory of Atoms in Molecules (QTAIM), Reduced Density Gradient (RDG), Electron Localization Function (ELF), and the Localized Orbital Locator (LOL), to gain insights into both intra- and intermolecular interactions. These findings strongly underscore the effectiveness of modifying the electron-donating group capability in D-π-A conjugated systems as a strategy for enhancing the optoelectronic properties of organic photovoltaic (PV) devices, as well as their NLO responses.

Electrochemical Conversion of High Pressure CO2

The electrochemical reduction of carbon dioxide (CO2R) via an electrochemical process is a strategic approach aimed at completing the carbon cycle for chemical production. Traditionally, this field has predominantly focused on conducting electrolysis on CO2 under standard atmospheric pressure. However, in industrial applications, CO2 is typically pressurized during its capture, transportation, and storage, often existing in a dissolved state. Our research has unveiled a significant discovery: subjecting aqueous CO2 to a pressure of 50 bar alters the CO2R pathways, favoring the formation of formate. This phenomenon is consistently observed across commonly used CO2R catalysts. Through the development of effective techniques for operating under high pressures, including a measurable Raman spectroscopy approach during the ongoing reaction, we have established a connection between the increased preference for formate and the heightened coverage of CO2 on the cathode surface. This collaboration between theoretical models and experimental data strongly supports this mechanism and has led us to enhance the cathode surface of a copper electrode with a proton-resistant layer. This innovation amplifies the selective impact caused by pressure. Furthermore, our research has unveiled the potential to transform gas-phase high-pressure CO2 into ethylene (C2H4) through CO2R. We conducted density functional theory calculations to identify a range of copper alloys that promote C-C dimerization under high pressure, which represents the rate-limiting step for C2H4 production. The theoretical predictions were validated through a combination of electrochemical measurements and operando observations, guiding us in designing a copper-based catalyst for efficient and active conversion of CO2 to C2H4.

SCAPS simulation and DFT study of ultra-thin lead-free perovskite solar cells based on RbGeI3

To reduce fossil fuel usage and mitigate greenhouse effects, we have developed an ultra-thin, more stable, and environmentally friendly all-inorganic perovskite solar cell (PSC). We demonstrated the excellent stability of the perovskite absorption layer (RbGeI3) at both micro- and macroscales. The SCAPS software optimized a range of parameters, such as initial structure thickness, bandgap, and defect density, based on continuity equations, Poisson's equation, and transport equations, investigating their impact on device performance. Compared to the pre-optimized state, the optimized fill factor (FF) increased by 26%, and power conversion efficiency (PCE) improved by 34%, while the total thickness was only 700 nm, indicating lower overall stress and increased stability of the device. Additionally, we conducted density functional theory studies on RbGeI3. State density indicated a high hybridization between Ge and I atoms, aiding in forming stable chemical bonds, which was further supported by electron configuration. Charge difference density revealed charge transfer between I and Ge, enhancing the performance of PSCs. Elastic properties demonstrated that RbGeI3 not only exhibited good mechanical stability but also had good toughness, reducing stress during PSCs operation, which is crucial for long-term stability. Our study offers guidance for the development of more stable PSCs.

SERS and machine learning based effective feature extraction for detection and identification of amphetamine analogs

Surface-enhanced Raman spectroscopy (SERS) is extensively researched in diverse disciplines due to its sensitivity and non-destructive nature. It is particularly considered a potential and promising technology for rapid on-site screening in drug detection. In this investigation, a technique was developed for fabricating nanocrystals of Ag@Au SNCs. Ag@Au SNCs, as the basic material of SERS, can detect amphetamine at concentrations as low as 1 μg/mL. The Ag@Au SNCs exhibits a strong surface plasmon resonance effect, which amplifies molecular signals. The SERS spectra of ten substances, including amphetamine and its analogs, showed a strong peak signal. To establish a qualitative distinction, we examined the Raman spectra and conducted density functional theory (DFT) calculations on the ten aforementioned species. The DFT calculation enabled us to determine the vibrational frequency and assign normal modes, thereby facilitating the qualitative differentiation of amphetamines and its analogs. Furthermore, the SERS spectrum of the ten mentioned substances was analysed using the support vector machine learning algorithm, which yielded a discrimination accuracy of 98.0 %.

A stable and conductive phthalocyanine-porphyrin two-dimensional carbon-rich conjugation frameworks for highly selective electroreduction of carbon dioxide to dimethyl carbonate

Electrocatalytic reduction of carbon dioxide (CO2RR) to long-chain chemicals, such as dimethyl carbonate (DMC), is considered an effective strategy for addressing excessive CO2 emissions. However, the underlying reaction mechanism remains unclear. In this work, based on phthalocyanine-porphyrin 2D CCFs, a tandem catalyst composed of Fe and other transition metals (TMs) co-embedded in rectangular extended Pc and TM-embedded in porphyrins is proposed. Among various catalysts, the Fe-Sc-Pc-Co-TPP-CCF catalyst stands out due to its unique catalytic sites that can efficiently convert both C1 and C2 intermediates simultaneously. This catalyst exhibits superior CO2 adsorption capacity and excellent catalytic activity, which can be attributed to the ability of the d orbitals of both Fe and TMs to accept lone pairs and feedback electrons from CO2. Additionally, the synergistic effect between the two different metals enhances the adsorption and activation of CO2 molecules. The detailed process of CO2 reduction to DMC on the Fe-Sc-Pc-Co-TPP-CCF catalyst was systematically investigated, and it was identified that the direct coupling of CO2 and methanol to form DMC is the optimal pathway. To evaluate the catalytic performance of the catalyst, we conducted density functional theory calculations. The results show that the Fe-Sc-Pc-Co-TPP-CCF catalyst exhibits an inhibitory effect on competing reactions of CO2RR, such as proton-coupling reaction and HER. Combined with DFT calculations, the reaction mechanism at the phthalocyanine-porphyrin 2D CCFs was systematically studied, providing novel insights into the potential pathway for the chemical conversion of CO2 into long-chain chemicals.

Cheminformatics bioprospection of selected medicinal plants metabolites against trypsin cleaved VP4 (spike protein) of rotavirus A

Rotaviruses have continued to be the primary cause of acute dehydrating diarrhoea in children under five years of age despite the global introduction of four World Health Organization (WHO) prequalified oral vaccines in over 106 countries. Currently, no medication is approved by the Food and Drug Administration (FDA) specifically for treating rotavirus A-induced diarrhoea. Consequently, it is important to focus on developing prophylactic and curative therapeutics to combat rotaviral infections. For the first time, this study computationally screened and identified metabolites from Spondias mombin, Macaranga barteri and Dicerocaryum eriocarpum as potential novel inhibitors with broad-spectrum activity against VP5* and VP8* (spike protein) of rotavirus A (RVA). The initial top 20 metabolites identified through molecular docking were further filtered using drug-likeness and pharmacokinetics parameters. The molecular properties of the resulting top-ranked compounds were predicted by conducting density functional theory (DFT) calculations, while molecular dynamics (MD) simulation revealed their thermodynamic compatibility with a significant affinity towards VP8* than VP5*. Except for ellagic acid (−11.78 kcal/mol), the lead compounds had higher binding free energy than the reference standard (VP5* (−11.81 kcal/mol), VP8* (−14.12 kcal/mol)) with 2SG (−20.98 kcal/mol) and apigenin-4'-glucoside (−23.56 kcal/mol) having the highest affinity towards VP5* and VP8*, respectively. Of all the top-ranked compounds, better broad-spectrum affinities for both VP5* and VP8* than tizoxanide were observed in 2SG (VP5* (−20.98 kcal/mol), VP8* (−20.13 kcal/mol)) and sericetin (VP5* (−20.46 kcal/mol), VP8* (−18.31 kcal/mol)). While the identified leads could be regarded as potential modulators of the investigated therapeutic targets for effective management of rotaviral infection, additional in vitro and in vivo evaluation is strongly recommended, and efforts are on-going in this regard. Communicated by Ramaswamy H. Sarma

CoO QDs/Bi2MoO6 monolayer: A novel S-scheme heterojunction for highly efficient photocatalytic C2H4 degradation

As a plant hormone, C2H4 causes significant economic losses during the storage and transportation of fruits and vegetables. How to efficiently photocatalytic oxidation of atmospheric C2H4 using sun-light remains a significant challenge at the frontiers of chemistry. Inspired by natural photosynthesis of plant, here, we design a novel S-scheme heterojunction for highly efficient photocatalytic C2H4 degradation. We first conducted density functional theory (DFT) calculations to predict an S-scheme heterojunction can be formed between CoO and Bi2MoO6, and then fabricated a novel CoO Quantum dots (QDs)/Bi2MoO6 monolayer S-scheme heterojunction by using a practical hydrothermal approach to in-situ deposit CoO QDs on a Bi2MoO6 monolayer. Furthermore, the UV–Vis DRS, UPS, in-situ XPS and electron spin resonance (ESR) characterization of DMPO-•O2– signals and DMPO-•OH signals evidence that the transfer pathway of space charge in photocatalytic degradation of ethylene accords with the S-scheme. Moreover, due to the unique structural design, CoO QDs and Bi2MoO6 monolayer form an S-scheme heterojunction, and the intimate contact that enables efficient charge transfer and sufficient redox ability simultaneously, the CoO QDs/Bi2MoO6 monolayer catalyst achieves a remarkable ethylene photocatalytic-degradation rate of 3.27 × 10−2∙min−1, 19.2 times higher than CoO and 22.5 times higher than Bi2MoO6. This work provides novel insights for designing efficient S-scheme photocatalysts for C2H4 degradation.

Chiral Oxazaborolidinium Ion (COBI)-Catalyzed Reaction of Aldimine with Tributyltin Cyanide: Mechanism and Origin of Stereoselectivity.

By conducting density functional theory (DFT) calculations, the detailed reaction mechanisms of aldimines with tributyltin cyanide under the catalytic influence of chiral oxazaborolidinium ion (COBI) have been uncovered. Three potential reaction pathways were examined, and two stereoselective routes were determined for the most energetically favorable mechanism. In the primary route, a proton is transferred from the COBI catalyst to the aldimine substrate, which is then followed by the C-C bond formation to produce the final product. Subsequently, NBO analyses of the stereoselectivity-determining transition states were conducted to identify the crucial role of hydrogen bond interactions in controlling stereoselectivity. These computed findings should prove invaluable in comprehending the detailed mechanisms and underlying origins of stereoselectivity for COBI-mediated reactions of this type.

Refined room-temperature equation of state of Bi up to 260 GPa

At room temperature, bismuth undergoes several structural transitions with increasing pressure before taking on a body-centered cubic (bcc) phase at approximately 8 GPa. The bcc structure is stable to the highest measured pressure and its simplicity, along with its high compressibility and atomic number, makes it an enticing choice as a pressure calibrant. We present three data sets on the compression of bismuth in a diamond anvil cell in a neon pressure medium, up to a maximum pressure of about 260 GPa. The use of a soft pressure medium reduces deviatoric stress when compared to previous work. With an expanded pressure range, a higher point density, and a decreased uniaxial stress component, we are able to provide more reliable equation of state parameters. We also conduct density functional theory electronic-structure calculations that confirm that the bcc phase is energetically favored at high pressure.

On the structural, electronic, and optical properties of L-histidine crystal: a DFT study.

The monoclinic L-histidine crystal is critical for protein structure and function and is also found in the myelin of brain nerve cells. This study numerically examines its structural, electronic, and optical properties. Our findings indicate that the L-histidine crystal has an insulating band gap of approximately 4.38 eV. Additionally, electron and hole effective masses range between 3.92[Formula: see text]-15.33[Formula: see text] and 4.16[Formula: see text]-7.53[Formula: see text], respectively. Furthermore, our investigation suggests that the L-histidine crystal is an excellent UV collector due to its strong optical absorption activity for photon energies exceeding 3.5 eV. To investigate the structural, electronic, and optical properties of L-histidine crystals, we used the Biovia Materials Studio software to conduct Density Functional Theory (DFT) simulations as implemented in the CASTEP code. Our DFT calculations were performed using the generalized gradient approximation (GGA) as parameterized by the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional, with an additional dispersion energy correction (PBE [Formula: see text] TS) based on the model proposed by Tkatchenko and Scheffler to describe van der Waals interactions. Additionally, we employed the norm-conserving pseudopotential to treat core electrons.

Target-learning the Latent Space of a Variational Autoencoder model for the Inverse Design of Stable Perovskites

At the forefront of discoverable materials are perovskites that stand out as some of the most chemically diverse and multifunctional energy materials. Theoretically, the estimated number of ternary perovskites exceeds a hundred thousand distinct compounds, notwithstanding that only a small fraction of this estimate has been reported in existing crystal databases. Therefore, the study takes advantage of the reliable, inexpensive and rapid opportunity offered by deep generative modeling for accelerating the search for unknown perovskites. In the process of making such findings, an inverse design-modeling scheme is resolved, which aims at assimilating deterministic target properties with their corresponding perovskite structure. The inverse design pipeline is architectured by combining a generative Variational AutoEncoder (VAE) model with Target-Learning (TL) feed-forward neural networks to form the TL-VAE perovskite generator, thereby making the complete modeling process semi-supervisory. The TL feed-forward neural network model serves the purpose of organizing the non-linear latent space of the VAE model and further assists in isolating deterministic target properties that are of interest to the core objective of the study. The property to be target-learned in the latent space is the formation energy, which is a crucial indicator for calibrating perovskite stability. The results report the discovery of promising new perovskite candidates, which are unique and polymorphic material variants. Upon conducting Density Functional Theory (DFT) validation on the newly identified perovskites, candidates that undergo full geometrical relaxation are recommended for further investigation and/or synthesization. In conclusion, the study demonstrates the efficacy of the inverse design TL-VAE model for the generation of stable ternary perovskites.

Exploring the Symmetry of Curvilinear Regression Models for Enhancing the Analysis of Fibrates Drug Activity through Molecular Descriptors

Quantitative structure-property relationship (QSPR) modeling is crucial in cheminformatics and computational drug discovery for predicting the activity of compounds. Topological indices are a popular molecular descriptor in QSPR modeling due to their ability to concisely capture the structural and electronic properties of molecules. Here, we investigate the use of curvilinear regression models to analyze fibrates drug activity through topological indices, which modulate lipid metabolism and improve the lipid profile. Our QSPR approach predicts the physicochemical properties of fibrates based on degrees and distances from topological indices. Our results demonstrate that topological indices can enhance the accuracy of predicting physicochemical properties and biological activities of molecules, including drugs. We also conducted density functional theory (DFT) calculations on the investigated derivatives to gain insights into their optimized geometries and electronic properties, including symmetry. The use of topological indices in QSPR modeling, which considers the symmetry of molecules, shows significant potential in improving our understanding of the structural and electronic properties of compounds.

Theoretical Investigation of Zero Linear Compressibility on Metal Squarates MC4O4 (M = Pb and Ba)

Zero linear compressibility (ZLC) and zero thermal expansion (ZTE) are unique and rare properties because of their excellent resistance to pressure and temperature, respectively. Metamaterials possessing both ZLC and ZTE will have promising application prospects. Herein, we conducted density functional theory studies on MC4O4 (M = Pb and Ba), which have “dumbbell”-like structures with ZTE property reported previously. The results show that the two compounds exhibit ZLC over the studied pressure range of 0 to 10 GPa along the c-axis, which is also the reported ZTE direction. Meanwhile, the ZLC can be furtherly tuned in value by replacing the metal element. The predicted ZLC phenomena in ZTE materials provide inspirations for designing and discovering new ZLC + ZTE metamaterials.