Safaei, S.,
Tangestaninejad, S.,
Moghadam, M.,
Bahadori, M.,
Mohammadpoor baltork, I.,
Omidvar, A.,
Mirzaeian, M. Journal of Industrial and Engineering Chemistry (1226086X)
Herein, vanadyl acetylacetonate and manganese(Ⅱ) acetylacetonate complexes were anchored into aminated UiO-66(Zr) via a condensation reaction (V-SB-UiO-66 and Mn-SB-UiO-66), where terminal amine groups formed imine linkage with the metal acetylacetonate complexes. Unlike conventional post-synthetic modification (PSM) strategies, our approach eliminates complex ligand exchange processes, offering a versatile platform for designing robust heterogeneous catalysts. This PSM approach, utilizing straightforward linker functionalization, introduces catalytic sites onto the MOF structure, facilitating heterogeneous catalytic epoxidation reactions. Comprehensive characterization techniques, including PXRD, N2 adsorption/desorption, FT-IR, FE-SEM, ICP-OES, TG-DTG, and XPS, confirmed the structural integrity during the PSM, successful anchoring of acetylacetonate complexes, the catalyst surface constitution and location of active Schiff-base functionalities on the UiO-66 scaffold. The density functional theory (DFT) calculations are also performed to investigate the pristine as well as functionalized MOFs. The structural and electronic properties, binding energies, reactivity descriptors, and time-dependent DFT (TD-DFT) analyses are performed to determine the behaviour of the considered systems. The catalytic performance of these Schiff base-functionalized UiO-66 s was evaluated for olefin epoxidation by tert-butyl hydroperoxide (TBHP) under various reaction conditions, achieving 44–99 % conversion and 57–96 % selectivity for cyclic, linear, and aromatic alkenes. Additionally, these catalysts demonstrated reusability for up to five cycles without significant structural changes. © 2025
Kargar, H.,
Fallah-mehrjardi, M.,
Moghadam, M.,
Omidvar, A.,
Zare-mehrjardi, H.R.,
Dege, N.,
Ashfaq, M.,
Munawar, K.S.,
Tahir, M.N. Polyhedron (02775387)249
In this study, a new 1D polymeric Cu(I) complex [Cu(L2Cl)I]n, where L = N,N′-bis(2-chlorobenzylidene)ethane-1,2-diamine, was synthesized and characterized using different analytical approaches, comprising 1H NMR, FT-IR, and CHN analysis. The geometrical features of the complex were determined through the single crystal X-ray diffraction (SC-XRD) method, which revealed that the copper atom is coordinated to the N atoms of the Schiff base. The bond angles surrounding Cu(I) ion indicated a somewhat distorted trigonal planar geometry of the complex. Hirshfeld surface analysis (HSA) was used to investigate the non-covalent intermolecular interactions, while theoretical studies were conducted utilizing DFT with B3P86/Def2-TZVP level of theory. The consistency between theoretical findings and experimental bond lengths of the [Cu(L2Cl)I]n confirmed the reliability of the theoretical conclusions. To better understand the intermolecular charge transfer features of the [Cu(L2Cl)I]n, the natural bond orbital as well as Atoms in Molecules analyses were also performed. The electrochemical behavior of the Cu(I) complex was explored at 25 °C using cyclic voltammetry in a pH 7.0 buffered solution. It is established that the quasi-reversible mechanism is consistent with the Cu(II)/Cu(I) redox system. Additionally, the catalytic action of this complex as a new catalyst was evaluated in the synthesis of derivatives of tetrahydropyrimidine by reacting 1,3-propylenediamine with various aryl nitriles under conventional thermal conditions. © 2023 Elsevier Ltd
Scientific Reports (20452322)14(1)
Motivated by recent study on synthesized N, N-diphenylaniline (DPA)-based dyes [DOI: https://doi.org/10.1016/j.solener.2022.01.062] for use in dye-sensitized solar cells (DSSCs), we theoretically design several dyes and explore their potential for enhancing the efficiency of DSSCs. Our designed dyes are based on the molecular structure of synthesized DPA-azo-A and DPA-azo-N dyes with a donor-π-bridge-acceptor (D-π-A) framework. In this research, we aim to develop the power conversion efficiency (PCE) of DSSCs by fine-tuning the molecular structure of the synthesized dyes. To this end, we focus on designing dyes by replacing the units of DPA-azo-A and DPA-azo-N with a variety of donor, π-bridge, and acceptor. Hence the density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations are done to explore their structure, electronic, optical, charge transport, and photovoltaic properties. Among all newly designed and reference dyes, the D3-azo-N and DPA-π3-N dyes which are designed by substituting the donor (DPA) and π-bridge (azo) units of DPA-azo-N with D3 and π3, respectively exhibit the highest PCE of 45.46% (for D3-azo-N) and 43.20% (for DPA-π3-N) and can be favorable dyes for improving the efficiency of DSSCs. Therefore, the dyes that are designed by substituting the donor and π-bridge units of synthesized dyes have more impact on improving the efficiency of DSSCs than those that involve replacing the acceptor units. Consequently, our theoretical findings will provide valuable insights for the experimentalists to employ these novel effective dyes and boost the performance of DSSCs. © The Author(s) 2024.
Journal of Molecular Liquids (18733166)410
Designing efficient electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is an important step of the water-splitting procedure, due to the expensive electrocatalysts and the energy loss because of overpotentials. Accordingly, in the present study and based on the newly synthesized copper-corrole complexes, several metallocorroles that can be used as electrocatalysts in water-splitting reaction were theoretically designed. The main objective of the present study is to investigate the electrocatalytic behavior of various metallocorroles toward OER at the anode as well as HER at the cathode. So, our focus will be on the corrole substrates incorporating Cr, Mn, Fe, Co, Ni, and Cu single atoms, nitrogen removal defective complexes, and Cl-functionalized corroles to explore the effect of structural modifications on the catalytic activity of metallocorroles. We found that the Ni- and Cr-corrole are encouraging catalysts for the OER and HER, respectively, outperforming the synthesized copper-based substrate and other designed metallocorroles with low overpotentials (ƞOER=0.68 V and ƞHER=0.10 V). The obtained Gibbs free energies confirm the feasibility of OER on a Ni single atom and HER on a Cr single atom of metallocorroles. The Volcano diagrams also reveal that the metallocorroles with better oxygen and hydrogen desorption correspond to the Ni- and Cr-corrole substrates, respectively. Generally, results show that our designed metallocorroles can be considered competent catalysts for water-splitting reactions. © 2024 Elsevier B.V.
Kargar, H.,
Fallah-mehrjardi, M.,
Moghadam, M.,
Yarahmadi, S.,
Omidvar, A.,
Zare-mehrjardi, H.R.,
Dege, N.,
Ashfaq, M.,
Munawar, K.S.,
Tahir, M.N. Inorganica Chimica Acta (18733255)570
Herein, we report the synthesis and spectroanalytical characterization of one-dimensional polymeric Cu(I) complex [Cu(L2Br)I]n, incorporating N,N′-bis(2-bromobenzylidene)ethane-1,2-diamine Schiff base ligand, L2Br. Single crystal X-ray diffraction (SC-XRD) was used to examine the specific organization of atoms in the complex. The results showed that the Cu ion was coordinated only through the N donor sites of the Schiff base. The complex's tetrahedral shape was distorted, as demonstrated by the bond angles around the metal atom. The natural bond orbital and atoms in molecules investigations were also carried out in order to gain greater knowledge of the Cu(I) complex's intermolecular charge transfer characteristics. The redox nature of the the complex was assessed by the cyclic voltammetry (CV) technique. The Cu(I)/Cu(II) redox arrangement has been observed to exhibit characteristics consistent with a quasi-reversible method. Furthermore, the catalytic activity of the Cu(I) complex was executed in the first-time synthesis of new tetrahydropyrimidine derivatives by treating various aryl nitriles with 2,2-dimethyl-1,3-propanediamine under conventional thermal conditions. A mechanism for the catalytic reaction was suggested and investigated by density functional theory (DFT). © 2024 Elsevier B.V.
Journal of Molecular Liquids (01677322)384
Based on the recently synthesized triphenylamine-based organic dyes [https://doi.org/10.1021/acsami.1c11547], several small molecules that can be considered as organic semiconducting materials in photovoltaic devices were theoretically modeled. It is found that these designed dyes with the donor-π conjugated bridge-acceptor (D-π-A) framework show high charge transport properties in the dye-synthesized solar cells (DSSCs). Divers types of π-bridges are explored and the structural, electronic, optical, and charge transport characteristics of considered organic small molecules are studied. Our results revealed the effect of π-bridge in tuning the charge transport properties of the studied dyes. Especially, it is found that the thiazole-based moieties as the most favorable candidate for π-bridges, can be used in the D-π-A backbone of the synthesized dye to improve the photovoltaic performance of the organic semiconductors. For designed organic dyes, the low electron reorganization energies and high intra-molecular coupling created by π-stacking give rise to improved electron and hole mobilities. This approach can be used for improving the semiconducting character of organic dyes in photovoltaic devices. © 2023 Elsevier B.V.
Journal of Molecular Liquids (01677322)383
Increasing the greenhouse gases in the atmosphere, mainly from human activities leads to the global warming phenomenon and poses a serious threat to life on the earth. Hence, there is a pressing need to mitigate greenhouse gases emission and overcome global warming. It is proven that Ionic liquids (ILs) and deep eutectic solvents (DESs) are fruitful materials to capture gases and reduce their emission. Here, we investigate the environmentally friendly and cost-effective cholinium geranate ([Cho][Ger]) IL and cholinium geranate:geranic acid ([Cho][Ger]:Ger acid) DES, for carbon dioxide (CO2) capture. To this end, the density functional theory (DFT) and molecular dynamics (MD) simulation approaches are employed to provide quantitative microscopic insight into the interactions between CO2 and IL/DES. The adsorption energies of IL…CO2 and DES…CO2 are explored through the DFT calculations and show stronger interaction between the IL…CO2 than DES…CO2. The MD simulation analyses including density profile, non-bonded energy, radial distribution function (RDF), and spatial distribution function (SDF) affirm the stronger interaction between the IL…CO2 than DES…CO2. Meanwhile, the DFT and MD simulation results reveal the strongest interaction between CO2 and [Ger] - anion of both IL and DES. Furthermore, the minimum potential of mean force (PMF) of CO2 at the IL-air interface represents the favorable adsorption of CO2 on IL. Overall, our molecular level findings which are not accessible through the experimental approaches could help experimentalists find high-efficient solvents for CO2 capture. © 2023 Elsevier B.V.
Synthetic Metals (03796779)297
Motivated by the synthesis of a covalent organic framework by condensation procedure of phenyl diboronic acid (denoted as COF-1), and the other theoretical studies of an energetically favorable (BO)18C36H24 unit cell, we investigate its potential as an anode material in the Li-ion battery (LIB). Using density functional theory method, we found that the COF-1 is a promising anode whose specific capacity of 513.98 mAhg-1 is higher than that of graphite, ψ-graphene and boron nanolayers (∼370 mAhg-1). Furthermore, energy diffusion barrier of Li-ions and the average voltage along the COF-1 anode are 0.34 eV and 0.85 V, respectively, which can deliver high operating voltage when linked to the cathode. These findings can pave the route for application of COFs with promising performance as the LIB anode. © 2023 Elsevier B.V.
Journal of Molecular Liquids (18733166)382
The authors regret: ACKNOWLEDGMENTS: We gratefully acknowledge the Iran National Science Foundation (INSF) and the University of Isfahan research council for supporting this work. This work is based upon research funded by Iran National Science Foundation (INSF) under project number 99025345. © 2023 Elsevier B.V.
Korbekandi, M.M.,
Mohammadpoor baltork, I.,
Moghadam, M.,
Tangestaninejad, S.,
Mirkhani, V.,
Omidvar, A.,
Notash, B. ACS Omega (24701343)8(18)pp. 15883-15895
The current study deals with the synthesis and characterization of a novel catalyst made from diphenhydramine hydrochloride and CuCl ([HDPH]Cl-CuCl). The prepared catalyst was thoroughly characterized using various techniques, such as 1H NMR, Fourier transform-infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis and derivative thermogravimetry. More importantly, the observed hydrogen bond between the components was proven experimentally. The activity of this catalyst was checked in the preparation of some new derivatives of tetrahydrocinnolin-5(1H)-ones via a multicomponent reaction between dimedone, aromatic aldehydes, and aryl/alkyl hydrazines in ethanol as a green solvent. Also, for the first time, this new homogeneous catalytic system was effectively used for the preparation of unsymmetric tetrahydrocinnolin-5(1H)-one derivatives as well as mono- and bis-tetrahydrocinnolin-5(1H)-ones from two different aryl aldehydes and dialdehydes, respectively. The effectiveness of this catalyst was further confirmed by the preparation of compounds containing both tetrahydrocinnolin-5(1H)-one and benzimidazole moieties from dialdehydes. The one-pot operation, mild conditions, rapid reaction, and high atom economy, along with the recyclability and reusability of the catalyst, are other notable features of this approach. © 2023 The Authors. Published by American Chemical Society.
Langmuir (15205827)39(14)pp. 5115-5128
In this study, 2-acrylamido-2-methylpropanesulfonic acid (AMPS)-doped polyaniline (PANI) fibers were used as polymerizable smart anticorrosive agents to prepare eco-friendly UV-curable anticorrosive coatings. For this purpose, AMPS-doped PANI fibers were synthesized through chemical oxidative interfacial polymerization. The size and chemical structure of the prepared conducting fibers were characterized by scanning electron microscopy, 1H NMR, and Fourier transform infrared (FTIR) analyses. As a binder for the prepared conducting fibers, an eco-friendly fluorinated urethane-methacrylate dispersion was synthesized and fully characterized using FTIR analysis. Subsequently, various amounts of the synthesized fibers were mixed with the fluorinated binder to prepare UV-curable anticorrosive coatings. The physicochemical interactions between the PANI fibers and UV-curable binder were studied thoroughly using differential scanning calorimetry and thermogravimetric analyses and measurement of the gel contents and adhesion strength of the prepared composite coatings. The corrosion resistance performance of the prepared coatings was evaluated using electrochemical impedance spectroscopy analysis, and the obtained results revealed that the presence of 2 wt % of the AMPS-doped PANI fibers significantly enhanced the corrosion resistance of the obtained coating. In addition, the corrosion layers of the coatings were analyzed using X-ray photoelectron spectroscopy, which indicated that the AMPS-doped PANI fibers changed the composition of the corrosion product layer. To expand these attempts, this study also explores the interaction of AMPS-doped PANI fibers with the Fe(100) surface using density functional theory as well as atom in molecule calculations. All of the obtained results proved that the outstanding corrosion protection performance of the prepared composite coatings originated from exceptional chemical interactions between the unsaturated doping agents of the prepared PANI fibers and the UV-cured polymer. © 2023 American Chemical Society.
Zadeh, F.G.,
Asadi, B.,
Mohammadpoor baltork, I.,
Tangestaninejad, S.,
Mirkhani, V.,
Moghadam, M.,
Omidvar, A. RSC Advances (20462069)13(44)pp. 31213-31223
Aminopropyl-1,3,5-triazine-2,4-diphosphonium tetrachloroferrate immobilized on halloysite nanotubes [(APTDP)(FeCl4)2@HNT] was prepared and fully characterized using different techniques such as FT-IR, thermogravimetric analysis (TGA), SEM/EDX, elemental mapping, TEM, ICP-OES, and elemental analysis (EA). This nanocatalyst was found to be highly effective for synthesis of various benzothiazole derivatives in excellent yields under solvent-free conditions. Furthermore, bis- and tris-benzothiazoles were smoothly synthesized from dinitrile and trinitrile in the presence of this catalytic system. High yields and purity, easy work up procedure, high catalytic activity (high TON and TOF) and easy recovery and reusability of the catalyst make this method a useful and important addition to the present methodologies for preparation of these vital heterocyclic compounds. © 2023 The Royal Society of Chemistry.
Molecular Physics (00268976)120(7)
Carbon/boron nitride heteronanotubes are now at the centre of experimental and theoretical studies because of their tunable properties and diverse applications. Herein, we investigate the charge transport and optical properties of carbon/boron nitride hybrid single- and double-walled nanotubes on the basis of first-principles calculations. Our results reveal that the C/BN heterojunctions with radial junctions parallel (horizontal) to the tube axis have more effects than the perpendicular (vertical) junctions on the charge transport properties of heteronanotubes. Furthermore, we find that the nonlinear optical response can be meaningfully controlled by altering the C/BN content and junction arrangement. In double-walled coaxial heteronanotubes, the interwall interaction is also found to increase the electron and hole transport rates noticeably and to have a major effect on the first hyperpolarizabilities of C/BN heteronanotubes. In contrast with coaxial carbon nanotubes, where the inner constituent is totally shielded by the outer tube, in our studied C/BN coaxial heteronanotubes, the inner shell is only partially shielded by the outer constituent. This study suggests a strategy to high-efficient design heteronanotubes with high charge transport properties and tunable nonlinear optical responses. Moreover, the designed C/BN heteronanotubes can discrete electrons and holes, suggesting their application in solar cell materials. © 2022 Informa UK Limited, trading as Taylor & Francis Group.
Physical Chemistry Chemical Physics (14639076)24(22)pp. 13988-13998
Rechargeable Li-ion batteries (LIBs) are one of the green energy storage devices that have been utilized in large-scale devices. Hence, improving the LIBs performance plays a crucial role in many industrial sectors. Herein, we introduce a novel electrode and electrolytes for improving the LIBs efficiency. The deep eutectic solvents (DESs) electrolytes based on lithium bis[(trifluoromethyl)sulfonyl] imide (Li[TFSI]) and two different ratios of 2,2,2-trifluoroacetamide (TFA): (Li[TFSI] : 2TFA and Li[TFSI] : 4TFA), and the calcium carbide monolayer (Ca2C-ML) MXene were used as an anode in the LIBs. The molecular dynamics (MD) simulation and density functional theory (DFT) calculations are performed to evaluate the interaction and orientation of DESs on Ca2C-ML. The density profiles, pair correlation functions, mean square displacement (MSD), diffusion coefficient, ionic conductivity, molecular orientation, and charge density profiles analyses are performed to determine the behavior of DESs on Ca2C-ML. The results indicate that in both DESs, the adsorption of Li+ cations and TFA species on the Ca2C surface is more than that of the [TFSI]− anions. However, the interaction of Li+ cations on the Ca2C surface in Li[TFSI]:2TFA is stronger than in Li[TFSI]:4TFA. Because the adsorption of Li+ on the Ca2C occurs favorably, the low intercalation potential of Li+ on the Ca2C anode can be predicted. Additionally, the simulations are carried out at higher temperatures (333.15 K, 353.15 K, and 373.15 K), and the enhancement in MSD, diffusion coefficient, and ionic conductivity is observed by increasing the temperature. Meanwhile, the low open-circuit voltage (0.30 V) during the Li-ion intercalation processes further shows the advantages of Ca2C MXene as a potential candidate for LIB anodes. Overall, it is hoped that these findings will provide guidance for the future design of high efficiency LIBs using the Li-based DESs electrolytes and novel MXene anodes. © 2022 The Royal Society of Chemistry
Physical Chemistry Chemical Physics (14639084)24(10)pp. 6215-6224
The diffusion of drugs into the cellular membrane is an important step in the drug delivery systems. Furthermore, predicting the interaction and permeability of drugs across the cellular membrane could help scientists to design bioavailable and high-efficient drugs. Discovering the COVID-19 drugs has recently drawn remarkable attention to tackle its outbreak. Due to the rapid replication of the coronavirus in the human body, searching for highly permeable drugs into the cellular membrane is vital. Herein, we performed the molecular dynamics (MD) simulation and density functional (DFT) calculations to investigate the permeability of keto and enol tautomers of the favipiravir (FAV) as well as hydroxychloroquine (HCQ) COVID-19 drugs into the cellular membrane. Our results reveal that though both keto and enol tautomers of the FAV are feasible to transfer through the cellular membrane, the keto form moves faster and diffuses deeper; however, the HCQ molecules aggregate in the water phase and remain near the cellular membrane. It is worth pointing out that the obtained results are consistent with the reactivity trends projected by the calculated reactivity descriptors of the considered drugs. Despite the pair correlation function and H-bond analyses revealing the interactions between the membrane and HCQ, the aggregation of the HCQ molecules resists their passage through the cellular membrane. Besides, the lower free energy barrier of FAV confirms its higher permeability than HCQ. These findings suggest that due to the deeper permeability of the FAV drug, its effectiveness can be more than that of HCQ. These molecular insights might help with a better understanding of the interactions between COVID-19 drugs and cellular membranes. Moreover, these theoretical findings could help experimental researchers find high-efficient strategies for COVID-19 therapy. This journal is © the Owner Societies
Journal of Molecular Liquids (18733166)339
More than fifty years have passed since the first Li-ion battery. However, Li-ion batteries are the revolutionary mobile energy storage devices of the present decade that still need improvement in efficiency. Herein, density functional theory calculations are used to study the application of boroxine covalent organic framework as anode materials in Li-ion batteries. Our results reveal that the lithium shows fast diffusion on the boroxine layer with a small energy barrier (0.30 eV). Also, the boroxine exhibits a high storage capacity of 827 mAh g−1, which stands among the largest storage capacity of the “two-dimensional” anode materials. Meanwhile, the low diffusion barrier in combination with the calculated low open-circuit voltage (0.70 V) during the Li-ion intercalation processes, further show the advantages of the boroxine layer as the potential candidate for the Li-ion battery anodes. © 2021 Elsevier B.V.
Computational and Theoretical Chemistry (2210271X)1198
Using density functional theory calculations, we design the novel materials with high nonlinear optical responses via linking the Li atom and Li3O superalkali to the [Rh2B18], [Ir2B18], [RhPdB18]+, [IrPtB18]+, [Pd2B18] 2+, and [Pt2B18] 2+ teetotum boron clusters. Our results reveal that the first static hyperpolarizability of the Li3O@M2B18, as a microscopic criterion of the nonlinear optical materials, are higher than the Li@M2B18 materials due to the higher electron-donating ability of the Li3O compared to the Li atom. Besides, the hyperpolarizability of the designed materials significantly increases along with the imposed external electric fields, representing that the nonlinear optical responses of the considered materials can be enhanced by applying the electric files parallel to the charge transfer direction. © 2021 Elsevier B.V.
Journal of Environmental Chemical Engineering (22133437)9(2)
One of the most exciting events in chemistry is the stable assemblies of atoms, denoted by superatoms, that could mimic the behaviors of elements in the periodic table. For the first time by Jena et al., a novel type of di-anions superchalcogens (BeAl122- and TiAu122-) has been introduced based on the various electron-counting rules. Inspired by the fascinating finding of these superatoms and guided by density functional theory calculations, we propose a novel and efficient strategy to capture pollutants from waste water via adsorbing the toxic heavy metal cations (Cd2+, Hg2+, and Pb2+) by the BeAl122- and TiAu122- superchalcogens. Our results reveal that the BeAl122- and TiAu122- superchalcogens were powerful to adsorb the Pb2+, Hg2+, and Cd2+ cations in the aqueous solution. Furthermore, by investigating the hydrated cations, the adsorption of hydrated [Pb(H2O)4]2+ on the BeAl122- and TiAu122- superatoms was found thermodynamically more favorable than the [Cd(H2O)4]2+ and [Hg(H2O)4]2+. Our calculations also showed that the adsorbing heavy metal cations can considerably narrow the wide HOMO-LUMO gap and remarkably enhance the first hyperpolarizability of the pristine BeAl122- and TiAu122- superchalcogens, due to electron transfer in this type of superatoms. Moreover, the results highlight the systems with higher electron transport rates, show the larger first hyperpolarizability as well as the higher nonlinear optical response. Time-dependent density functional calculations also revealed "ligand to metal charge transfer"vertical excitations for the cation/superchalcogen systems. However, these theoretical findings might be helpful for experimental scientists toward designing high-efficient adsorbents based on superatoms for eliminating water pollutants. © 2020 Elsevier Ltd.
Mohammadpour, Z.,
Abdollahi, S.H.,
Omidvar, A.,
Mohajeri, A.,
Safavi, A. Journal of Molecular Liquids (18733166)309
Deep eutectic solvents (DESs) have found great interest among researchers due to their green nature and lower costs compared to organic solvents and ionic liquids. Water, an essential component of most DESs, poses paramount impacts on the properties of these solvents. In the present study, we found that water can modulate the molecular arrangement of the solvent and affect the synthesis efficiency of both MoS2 and graphene nanosheets considerably. Using a low-cost mechanical exfoliation approach and response surface methodology, we achieved the synthesis yield of 87% for MoS2 nanosheets. We also succeeded in the production of few-layer graphene with the average lateral dimension of 3.5 μm. We further showed that it is possible to dilute DESs by water and still retain the synthesis yield at reasonably high levels. In this way, the total cost of the exfoliation process reduces, particularly when it is aimed to synthesize large scales of two-dimensional nanomaterials. © 2020 Elsevier B.V.
ACS Applied Energy Materials (25740962)3(11)pp. 11463-11469
The performance of Li-ion batteries (LIBs) depends upon anode materials with high capacity. Motivated by the recent synthesis of a carbon nanocone (CNC), which includes a pentagon encircled by 30 hexagons using a palladium-catalyzed cross-coupling reaction, we investigate its potential for a LIB anode material. Density functional theory (DFT) calculations are performed to examine the potential application of the CNC layer with topological defects as an anode material in the LIBs. The Stone−Wales (SW)-defect-filled CNC (CNC-SW) layer exhibits a more negative Li binding energy than the pristine CNC (CNC-PR). We found that the Li atom exhibits fast diffusion on the surface of both the CNC-PR and CNC-SW layers with the low energy barriers of 0.38 and 0.32 eV, respectively. Also, both the CNC-PR and CNC-SW layers show high storage capacities of 843 and 893 mAh g−1, which are standing among the largest storage capacities of the carbon-based anodes for LIBs. Moreover, the Li atoms intercalated CNC-SW layer show a low open-circuit voltage (VOCV) of 0.59 V. Thus, our results reveal that the CNC is a promising material for application as an anode in the LIBs. As the existence of the CNC layer is experimentally confirmed, the results reported in this study can be helpful for further improving the performance of anode materials in the LIBs. © 2020 American Chemical Society
Journal of Molecular Liquids (01677322)312
To address the enhancing request of appropriate photovoltaic materials for application in renewable energy resources, an attempt has been made herein to design and investigate the novel porphyrin-based donors with higher transport properties. The interesting furan-linked porphyrin donor (FPD) and thiophene-linked porphyrin donor (TPD) containing Zn metal atom have been previously synthesized and applied into the organic solar cell. Inspired by this fascinating finding, we suggest a new set of porphyrin-based donors with high charge transport properties via designing molecular scaffolds with different numbers of coordinated nitrogen atoms (FPD-Nx and TPD-Nx, x = 0–4) and various types of metal atoms (FPD-M and TPD-M, M = Fe, Co, Ni, Cu, and Zn). Then, the structural, electronic, optical, and charge transport properties of the designed donors have been studied and compared with the available experimental results. Our calculations reveal that the FPD-N2, TPD-N2, FPD-Co, and TPD-Co porphyrins possess the planar structures, proper energy levels in reference to the PCBM acceptor, high open-circuit voltage (VOC), and excellent charge transport properties which make them ideal donors that are used in organic solar cells. Accordingly, our predicted donors represented the improvement in the structural and transport properties which may lead to organic solar cells with high power conversion efficiency. Consequently, this approach can be useful for further improving the efficiency of porphyrin donors in organic solar cells. © 2020 Elsevier B.V.
Journal of Chemical Information and Modeling (15499596)59(5)pp. 1930-1945
On the basis of the newly synthesized banana-shaped thieno[3,2-b] pyrrole building block [Bulumulla, C.; Gunawardhana, R.; Kularatne, R. N.; Hill, M. E.; McCandless, G. T.; Biewer, M. C.; Stefan, M. C. Thieno[3,2-b] pyrrole-Benzothiadiazole Banana-Shaped Small Molecules for Organic Field Effect Transistors. ACS Appl. Mater. Interfaces 2018, 10, 11818-11825], several small molecules that can be used as organic semiconducting materials were theoretically designed. We have shown that these novel molecules with the donor-πconjugated bridge-acceptor-πconjugated bridge-donor (D-π-A-π-D) building block exhibit superior charge transport properties in organic field-effect transistors (OFETs). A variety of donors, π-bridges, and acceptors are examined, and the structural, electronic, optical, and charge transport properties of designed semiconductors are systematically investigated. The results highlight the impact of the core acceptor in improving the transport properties of the designed molecules. In particular, this work points toward the benzo-bis(1,2,5-thiadiazole) as the most promising acceptor that can be combined with thiophene π-bridge and flanked benzo-thiadiazole terminal units to produce a reasonable candidate for synthesis and for incorporating into OFET materials. For the suggested semiconductor, the small electron reorganization energy and large intramolecular coupling originating from dense π-stacking gave rise to enhanced electron mobility. This strategy can be helpful for further improving the performance of curved small molecules in field-effect devices. © 2018 American Chemical Society.
Applied Surface Science (01694332)434pp. 1239-1247
Metal particles supported on metal oxides (MMO) are promising materials with versatile applications such as catalyst in fuel cell technologies. As one of the transition metal oxides, niobium oxide (NbO) demonstrates a wide interesting properties that make it a potentially applicable in MMO materials. Here, the catalytic activity for the O 2 activation of transition metals (Fe, Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au) supported on the NbO has been studied theoretically using density functional theory (DFT). The activation of O 2 molecule and yielding two separated O atoms is an essential step for the oxygen reduction reaction. Our study demonstrates that the transition metals supported on the NbO can act as driving force for O 2 dissociation. Consistent with the prediction of reactivity descriptors, the maximum catalytic activity toward O 2 activation is related to the Pt-supported on the NbO metal oxide. © 2017 Elsevier B.V.
Surface Science (00396028)668pp. 117-124
Electrical charging of an FeN4 cluster embedded in graphene (FeN4G) is proposed as an approach for electrocatalytically switchable carbon monoxide (CO) adsorption. Using density functional theory (DFT), we found that the CO molecule is strongly adsorbed on the uncharged FeN4G cluster. Our results show that the adsorption energy of a CO molecule on the FeN4G cluster is dramatically decreased by introducing extra electrons into the cluster. Once the charges are removed, the CO molecule is spontaneously adsorbed on the FeN4G absorbent. In the framework of frontier molecular orbital (FMO) analysis, the enhanced sensitivity and reactivity of the FeN4G cluster towards the CO molecule can be interpreted in terms of interaction between the HOMO of CO molecule and the LUMO of FeN4G cluster. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Our study indicates that the FeN4G nanomaterial is an excellent absorbent for controllable and reversible capture and release of the CO. © 2017 Elsevier B.V.
Inorganic Chemistry (00201669)57(15)pp. 9335-9347
Presently, many researches are directed toward the design of novel superatoms with high nonlinear optical responses. Inspired by a fascinating finding of superatoms which were designed by bonding superhalogen (Al13 nanocluster) with superalkalis (M3O, M = Na and K), we suggest an effective strategy to form a series of typical donor-acceptor frameworks with high nonlinear optical responses via bonding the superalkalis M3O (Li3O, Na3O, K3O, Li2NaO, Li2KO, Na2LiO, Na2KO, K2LiO, K2NaO, and LiNaKO) with low ionization potential to the superhalogen Al13 with large electron affinity. The ionization potential, electronic spatial extent, electric field gradient tensors of 17O nuclei, and natural bond orbital charge values of the superalkalis M3O were also calculated. We found that the M ligands have the remarkable effect on the ionization potential as well as 17O nuclear quadrupole resonance parameters of the superalkalis M3O. Our results also represented that the bonding superalkalis can efficiently narrow wide HOMO-LUMO gap and considerably enhance first hyperpolarizability of the pristine Al13, due to electron transfer in this type of superatom. Also, the effect of oriented external electric fields on the nonlinear optical responses of the superatoms M3O-Al13 has been systematically explored. We found that the first hyperpolarizability of the superatom compounds can be gradually increased by increasing the imposed oriented external electric field from zero to the critical external electric field along the charge transfer direction (M3O → Al13). In this respect, this work reveals an effective approach to gradually enhance the nonlinear optical responses of the superatoms through applying oriented external electric fields. © 2018 American Chemical Society.
Synthetic Metals (03796779)241pp. 39-46
Increasing concerns about capture and separation of CO2 and its impact on the global warming are motivating researchers to discover new materials and strategies for efficient CO2 capture. Here, we explored the possibility of conductive Fe/Nx clusters embedded in graphene (Fe/Nx/G) as an adsorbent for electrocatalytically switchable CO2 capture. Using density functional theory including long-range dispersion corrections, we investigated the adsorption process of CO2 on Fe/Nx/G (x = 0, 2, and 4) systems with various charge states. We found that CO2 molecule - forms weak interaction with the neutral Fe/Nx/G systems. On the contrary, the adsorption behavior of CO2 molecule on the Fe/Nx/G systems can be significantly enhanced by adding extra charges into the Fe/Nx/G. Our results show that by removing the charges, CO2 molecule automatically desorbs from Fe/N4/G. Thus, by switching on/off the charges carried by Fe/Nx/G systems the CO2 capture/release procedures can be easily controlled without any energy barrier. Moreover, these Fe/Nx/G systems are highly selective for separating CO2 from its mixtures with methane, hydrogen, and nitrogen. These predictions open the route for the further studies of charge-modulated systems with switchable capture/release capabilities that present high selectivity for CO2. © 2018 Elsevier B.V.
Vacuum (0042207X)147pp. 126-133
Indium-doped ZnO nanoparticle has been recently synthesized using a modified sol-gel technique. This study has revealed that the In-doped ZnO nanoparticles represent a higher sensitivity than the pristine ZnO nanoparticles to the carbon monoxide gas and can detect it at sub-ppm concentrations. Motivated by this study, in the present work using first-principles calculations, we study the effect of In-doping on the sensing properties of a ZnO nanocluster. In our survey, we have explored the sensitivity of pristine as well as In-doped ZnO nanoclusters towards CO detection. In contrast to the pristine form, the In-doped ZnO nanocluster can detect the CO molecule due to significant decrease in the HOMO-LUMO energy gap and thereby in the resistivity. As a secondary objective of the present study, electrical charging of the ZnO nanocluster is proposed as an approach for electrocatalytically switchable CO adsorption. We found that the CO molecule is weekly adsorbed on the neutral ZnO nanocluster. Our results show that the interaction between CO molecule and ZnO nanocluster is dramatically increased by introducing extra positive charges into the nanocluster. Once the charges are removed, the CO molecule spontaneously desorbed from the ZnO absorbent. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. © 2017 Elsevier Ltd
Computational and Theoretical Chemistry (2210271X)1115pp. 179-184
Elemental boron is electron-deficient and cannot form graphene-like structures. Instead, triangular boron lattices with hexagonal vacancies have been predicted to be stable. Recently, experimental and theoretical studies showed that the B36 sheet has a planar C6V structure with a central hexagonal hole, providing the first experimental evidence for the viability of atom-thin boron sheets with hexagonal vacancies, dubbed borophene. Herein, the sensitivity of the B36 borophene toward HCN molecule is theoretically investigated. The electronic properties of HCN/borophene adducts are strongly dependent on the molecular adsorption configuration. Owing to strong interactions between HCN and the B36 borophene, dramatic changes in the electronic properties of the sheet together with large HOMO-LUMO gap variations were observed. We found that the adsorption of HCN molecule can significantly influence the electronic structure of B36 borophene. Our results demonstrate that the B36 nanosheet is sensitive to the concentration (or pressure) of HCN gas. Our predictions can serve a guideline for further theoretical and experimental researches in investigating the electronic properties of the B36 borophene nanosheet. © 2017 Elsevier B.V.
Journal of Molecular Graphics and Modelling (10933263)77pp. 218-224
The activation of the O2 molecule and yielding two separated O atoms is an essential step for the oxygen reduction reaction processes. Dissociation of the strong bond in the O2 often involves large activation barriers on metal particles used as catalysts. Here, the catalytic activity for the O2 dissociation of the transition metals (Fe, Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au) deposited on the BN nanocluster have been studied theoretically using density functional theory. The following outcomes can be derived from our calculations: (1) The strong interaction between the Fe and Ni metal atoms and boron atom in BN nanocluster suggests that these transition metals deposited on BN nanocluster should be stable under high temperatures. (2) Transition metal deposition enhances the reactivity of BN nanocluster, however, it is more effective in the case of Fe-deposited on BN nanocluster. (3) Consistent with the prediction of reactivity descriptors, the maximum catalytic activity toward O2 dissociation is related to the Fe-deposited on BN nanoclusters. (4) The adsorption energies of the O2 adsorbed on the metal-deposited BN nanoclusters increase with the increase transition metals positive charges. (5) The energy barrier of the O2 dissociation is significantly decreased by introducing extra positive charges into the metal deposited on the BN nanocluster. Our study demonstrates that the transition metals-deposited on the BN nanoclusters can act as driving force for O2 dissociation. These predictions open the route for the experimental studies of catalysts that offer high activity for oxygen reduction reaction processes. © 2017 Elsevier Inc.
International Journal of Hydrogen Energy (03603199)42(17)pp. 12327-12338
The metal decorated fullerenes form a new class of important nanostructured materials with various potential applications. This work presents a comprehensive study to investigate the decoration of a series of alkali metals (Li, Na, and K) on pristine fullerene (C60) as well as boron-doped (BC59) and aluminum-doped (AlC59) structures. In the framework of density functional theory (DFT), we analyze the effects of metal decoration on the structure, stability, reactivity and electronic properties of considered fullerenes. The obtained reactivity patterns for considered metallofullerenes are validated by explicit adsorption of H2 molecule. The following outcomes can be derived from our calculations: (1) Alkali metal decoration enhances the reactivity of considered cages, however, it is more effective in the case of AlC59. (2) Whereas the boron or aluminum doping of C60 does not alter the static dipole polarizability of the fullerene, metal decoration induces more pronounced effect on the cage polarizability. Moreover, the static dipole polarizability of pristine C60 and AlC59 fullerenes are more sensitive to metal decoration (3) Atoms in molecules analysis show that the interactions between alkali metal atoms and pristine as well as doped-C60 are noncovalent with electrostatic dominant character. (4) Consistent with the prediction of reactivity descriptors, the maximum binding strength for H2 adsorption is related to the K/AlC59 system. However, we envisage that the outcomes of current study can stimulate further researches in this area, particularly in manipulating fullerene materials for designing promising hydrogen storage medium. © 2017 Hydrogen Energy Publications LLC
Synthetic Metals (03796779)234pp. 38-46
The O2 dissociation and yielding two separated O atoms is an essential step for the oxygen reduction reaction. Dissociation of the strong bond in the O2 often involves large activation barriers on metal particles used as catalysts. Here, the O2 dissociation on the Fe/Nx clusters embedded in the fullerene C60, carbon nanotube, and graphene nanomaterials have been studied theoretically using density functional theory. The following outcomes can be derived from our calculations: (1) The Fe/Nx clusters embedded in the C60, carbon nanotube, and graphene enhance the reactivity of these nanomaterials, however, it is more effective in the case of Fe/Nx clusters embedded in the graphene. (2) Consistent with the prediction of the reactivity descriptors, the maximum catalytic activity toward the O2 dissociation is related to the Fe/N4 cluster embedded in graphene. (3) The adsorption energies of the O2 adsorbed on the Fe/Nx clusters embedded in the C60, carbon nanotube and graphene increase with the increase Fe transition metal positive charges. (4) Our study demonstrates that the Fe/N4 cluster embedded in graphene can act as driving force for the O2 dissociation. (5) The energy barrier of the O2 dissociation process shows that the O2 dissociation on the Fe/N4 cluster embedded in the graphene will be kinetically preferable. These predictions open the route for the experimental studies of catalysts that offer high activity for oxygen reduction reaction processes. © 2017 Elsevier B.V.
Materials Chemistry and Physics (02540584)202pp. 258-265
Opening a bandgap in graphene is one of the most important subjects in the graphene research currently, since most of the suggested applications for graphene in field-effect transistors and optoelectronic devices require the ability to adjust its bandgap. To solve this problem, a novel graphene-like nanomaterials, i.e. a nitrogenated holey graphene has been recently synthesized using a simple wet-chemical reaction (Nat. Commun. 2015, 6, 6486). Motivated by this experimental work, in the present study, the structural and electronic properties of the zero dimensional (0D) holey graphene flake are investigated using first-principles calculations. In the framework of density functional theory, we analyze the effects of number of doped atoms (nitrogen and boron) on the structure, stability, and electronic properties of the holey graphene flake. In our survey, we have explored the stability of pristine as well as doped and co-doped holey graphene flake by studding of band gap energy as well as cohesive energy, chemical hardness, hyper-hardness, electrophilicity index, and dipole moment values of the considered flakes. The present study opens the way for manipulating holey graphene and developing promising materials for applications in field-effect transistors and optoelectronic devices. © 2017 Elsevier B.V.
Chemical Physics (03010104)493pp. 85-90
Electrical charging of Co/N4 cluster embedded in graphene (Co/N4/G) is proposed as an approach for electrocatalytically switchable hydrogen adsorption. Using density functional theory, we found that the H2 molecule is weakly adsorbed on the uncharged Co/N4/G cluster. Our results show that the adsorption energy of hydrogen molecule on Co/N4/G cluster is significantly increased by introducing extra positive charges into the cluster. Once the charges are removed, H2 molecule spontaneously desorb from the Co/N4/G absorbent. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Our study indicates that the Co/N4/G nanomaterial is excellent absorbent for controllable and reversible adsorption and release of H2. © 2017 Elsevier B.V.
Mohammadpour, Z.,
Safavi, A.,
Omidvar, A.,
Mohajeri, A.,
Mobaraki, N.,
Shamsipur, M. Journal of Fluorine Chemistry (00221139)190pp. 12-22
In this work, a new type of water soluble fluorescent assay was designed for fluoride ion based on the inner filter effect (IFE) of simple para-substituted arylboronic acids. Carbon nanodots (CDs) as the green and nontoxic carnbonic nanomaterials were used as the fluorophores and arylboronic acids as the absorbers. The reaction of fluoride ion with boron center of arylboronic acids tuned the absorption profiles toward longer or shorter wavelengths. In case of an increase in the spectral overlap between absorber and fluorophore, a decrease in fluorescence intensity of CDs was observed and considered as a response for quantitative fluoride measurement. The minimum detectable value of fluoride by these assays fulfilled the Environmental Protection Agency (EPA) requirement for water safety. The simple design of this assay together with avoidance of any covalent linkage between fluorophore and absorbers offers a cost effective, selective and sensitive fluoride sensor in aqueous environments. Furthermore, we have carried out density functional theory calculations to study the electronic structures and optical absorption spectra of the arylboronic acids before and after reaction with fluoride. Excellent agreement between the experimental result and theoretical calculations enables for prediction of spectral change of aryl boronic acids upon reaction with fluoride. In particular, the effect of fluoridation reaction on the excitation spectrum of CDs through IFE could be simply predicted by the theoretical calculation. Therefore, by using the present system, design of even more successful probes would be feasible for fluoride recognition in aqueous media. © 2016
Mandegani, Z.,
Asadi, M.,
Asadi, Z.,
Mohajeri, A.,
Iranpoor, N.,
Omidvar, A. Green Chemistry- England (14639262)17(6)pp. 3326-3337
A new nano tetraimine Pd(0) complex was successfully prepared by the complexation of palladium acetate with an N,N-bisimine ligand. The structural features of the catalyst and the ligand were characterized using different microscopic and spectroscopic techniques such as FT-IR, XRD, XPS, UV-Vis, NMR, and elemental analysis. The morphology of the catalyst was determined using FE-SEM and TEM. The catalyst was effectively employed in the palladium-catalyzed Heck-Mizoroki reaction in water as a green solvent. The catalyst was reusable and recycled six times without any decrease in its catalytic activity. The ICP analysis showed that the catalyst has very little Pd leaching (0.2%) during the reaction process, demonstrating that our catalyst is stable and heterogeneous in practice. Furthermore, we have theoretically explored the feasibility of two neutral and cationic pathways in the density functional theory framework. The geometries and energies of all species involved in the reaction mechanism are analyzed. © The Royal Society of Chemistry 2015.
Molecular Physics (00268976)113(23)pp. 3900-3908
The sensitivity of a new two-dimensional (2D) carbon allotrope built from sp- and sp2-hybridised carbon atoms, graphyne (GY), as well as its boron nitride analogue (BN-yne) towards CO molecule has been theoretically investigated. Indeed, a theoretical understanding of the interaction between gas molecules and extended carbon-based network structures is crucial for developing new materials that could have a wide range of applications. Here, we report our first-principles calculations to explore the impact of metal decoration on the GY and BN-yne upon the CO adsorption. We predict that Ca and Li decorations significantly enhance the CO-sensing ability of the GY and BN-yne compared to that of their pristine sheets. Owing to strong interactions between CO and the decorated GY and BN-yne, dramatic changes in the electronic properties of the sheets together with large band gap variations were observed. The present study sheds a deep insight into the sensing properties of the novel carbon-based 2D structures beyond the graphene sheet. © 2015 Taylor & Francis.
Physical Chemistry Chemical Physics (14639076)17(34)pp. 22367-22376
Fossil fuel alternatives, such as solar energy, are moving to the forefront in a variety of research fields. Polymer solar cells (PSCs) hold promise for their potential to be used as low-cost and efficient solar energy converters. PSCs have been commonly made from bicontinuous polymer:fullerene composites or so-called bulk heterojunctions. The conjugated polymer donors and the fullerene derivative acceptors are the key materials for high performance PSCs. In the present study, we have performed density functional theory calculations to investigate the electronic structures and magnetic properties of several representative C60 fullerene derivatives, seeking ways to improve their efficiency as acceptors of photovoltaic devices. In our survey, we have successfully correlated the LUMO energy level as well as chemical hardness, hyper-hardness, nucleus-independent chemical shift, and static dipole polarizability of PC60BM-like fullerene derivative acceptors with the experimental open circuit voltage of the photovoltaic device based on the P3HT:fullerene blend. The obtained structure-property correlations allow finding the best fullerene acceptor match for the P3HT donor. For this purpose, four new fullerene derivatives are proposed and the output parameters for the corresponding P3HT-based devices are predicted. It is found that the proposed fullerene derivatives exhibit better photovoltaic properties than the traditional PC60BM acceptor. The present study opens the way for manipulating fullerene derivatives and developing promising acceptors for solar cell applications. © the Owner Societies 2015.
RSC Advances (20462069)5(67)pp. 54535-54543
The adsorptions of several gas molecules (O2, N2, CO, and NO) on functionalized graphene nanoflakes (GNFs) have been investigated. Three electron donating functional groups including -OH, -NH2 and -NHCHO are considered to improve the gas sensing behavior of GNF. The electronic properties of gas/GNF adducts are strongly dependent on the functional group and on the molecular adsorption configuration. Adsorption of NO molecule can significantly influence the electronic properties of functionalized GNFs, while adsorptions of O2, N2, and CO molecules have little effect. The most effective functional group is -NHCHO which has a prominent role in the enhancement of both sensitivity and reactivity of GNF toward NO. The strong interactions between NO and functionalized GNFs induce dramatic changes to the GNF's electronic properties and lead to large opening of the band gap. The introduced sensors also preserve their sensitivity under humid conditions. Our quantitative study on the impact of functionalization on the gas/GNF interaction has relevance for devising chemical modification strategies for designing selective carbon-based gas sensors. © The Royal Society of Chemistry.
Physical Chemistry Research (23225521)3(2)pp. 89-98
Magnesium oxide nanoclusters have attracted much attention due to their potential applications to catalysis and novel optoelectronic materials. In the present study, we have studied the electronic and magnetic properties of the stoichiometric magnesium oxide nanoclusters (MgO)n for n = 2-20. Although the binding energy increases with the size of the cluster, it reaches the asymptotic limit of about 66.0 eV per unit for relatively large n value. The static dipole polarizability also exhibits distinct size dependence, reflecting clearly the structural transition when the cluster grows. The polarizability and the binding energy of the clusters are found to be inversely related to each other and their correlation is rationalized by invoking the minimum polarizability principle. Moreover, principle of maximum hardness is also used to characterize the magic number clusters. A well-defined linear correlation is found between static dipole polarizability and the inverse of ionization potential. The most important feature of this work is the NMR study of MgO clusters which is reported for the first time. For each cluster size, the calculated NMR parameters at 17O nuclei together with electronic and structural data provide detailed insight into the properties of bulk and in particular of nanosized structures. Variation of 17O chemical shieldings demonstrates the electrostatic environment divisions around the oxygen nuclei which in turn originate from the cluster structure and its symmetry.
Journal of Physical Chemistry C (19327455)118(3)pp. 1739-1745
Optical and electronic properties are evaluated for infinite periodic boron nitride nanotubes (BNNTs) within density functional theory framework. Specifically, the static dipole polarizability and the band gap of the single-walled zigzag and armchair tubes as well as the double-walled zigzag nanotubes are calculated. Four density functional methods of different categories, namely, PBE, TPSS, VSXC, and HSE have been considered for our purpose. Our results allow promising application of the HSE functional in predicting band gap of infinite periodic nanotubes and similar compounds. The behaviors of DFT methods we obtained for single-walled boron nitride nanotubes are also preserved for predicting the band gap and shielding efficiency of double-walled BNNTs. In double-walled coaxial tubes, the interwall interaction is found to reduce the band gap distinctly and to have only minor effects on the polarizabilities of constituent tubes. In contrast with multiwalled carbon nanotubes, where the inner tube is almost completely shielded by the outer tube, in the studied double-walled BNNTs the inner tube is only partially shielded by the outer shell. This study has implication for nanoelectronics and specifically suggests a new route to efficiently design novel nanodevices with tunable gaps. © 2014 American Chemical Society.
Sensors and Actuators, B: Chemical (09254005)202pp. 622-630
Graphene nanoribbon has a great potential to be used in the future electronic applications. Working on desirable properties by modifying nanoribbons by appropriate elements or functional groups helps us find the suitable form of graphene nanoribbon for each application. The main goal of the present study is to exploit the potential applicability of using finite graphene fragments referred to graphene nanoflakes (GNFs) as gas sensor. For this purpose, the interactions between small gas molecules (O2, N 2, CO and NO) and six different armchair GNFs including pristine, B- or N-doped as well as functionalized GNFs with COOH, CN, and NO2 have been investigated. We found that the pristine, B- and N-doped and also functionalized GNF are not sensitive to N2, O2 and CO. On the other hand, while the pristine GNF shows sensitivity and reactivity to NO molecule, functionalization of GNFs, particularly, by carboxylic functional group prompts both sensitivity and reactivity of the GNF toward NO. The strong interactions between the NO and the functionalized GNFs induce dramatic changes to GNF's electronic properties and lead to large opening of the band gap of the nanoflake. However, the results of this study open the ways to manipulate graphene nanoflakes and development of new and effective sensors based on functionalized nanoflakes. © 2014 Elsevier B.V.
Scientia Iranica (10263098)20(3)pp. 1014-1017
We have performed Density Functional Theory (DFT) calculations to investigate the influence of carbone nanotube (CNT) size on the properties of the electronic structure of various junction models constructed from (6, 0) CNT and graphene nanoribbon (GNR) units via covalent linkage. Chemical shielding tensors and the HOMO-LUMO gap have been calculated for different models of the investigated hybrids of CNT and GNR. Our results indicate that the HOMO-LUMO gap strongly depends on the number of atoms and tube length, showing a decreasing trend with increasing the length of the tube and approaching zero in Model 7. The isotropic and anisotropic Chemical Shift (CS) parameters are divided into some layers, based on detecting similar electronic environments for the atomic sites of each layer. © 2013 Sharif University of Technology. Production and hosting by Elsevier B.V. All rights reserved.
Journal of the Iranian Chemical Society (17352428)10(6)pp. 1239-1246
Using first-principle density functional theory calculations, various junctions models constructed from (6, 0) carbon nanotube and graphene nanoribbon units via covalent linkage have been envisioned. Dipole moments, energy gaps, linking bond lengths and angles, quadrupole coupling constants are the obtained parameters. Frontier molecular orbital (FMO), molecular electrostatic potential surface (MEP) analyses and all energy calculations were performed at B3LYP/6-31G (d) level of theory. © 2013 Iranian Chemical Society.
Ahmadi peyghan, A.,
Omidvar, A.,
Hadipour, N.L.,
Bagheri, Z.,
Kamfiroozi, M. Physica E: Low-Dimensional Systems and Nanostructures (13869477)44(7-8)pp. 1357-1360
The sensitivity of aluminum nitride nanotubes (AlNNTs) to NH 3 molecules was investigated using DFT calculations. It was found that NH 3 molecule cannot be detected by pristine AlNNTs, since it cannot change the HOMO-LUMO energy gap (E g) of the tube upon adsorption process. Our results demonstrated that doping an oxygen atom in the vicinity of adsorption site makes the AlNNT electrical conductivity strongly sensitive to the NH 3 molecule. It suggests that O-doped AlNNT would be a potential candidate for the NH 3 molecule detection. The present results provide guidance to experimental scientists in developing nanotube-based chemical sensors. © 2012 Elsevier B.V.
