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In this paper, structural and dynamical properties of ibuprofen and ketoprofen glass-forming liquids have been investigated by means of molecular dynamics simulations. Molecular mobility of both materials is analyzed with respect to the different inter-molecular linear/cyclic hydrogen bonding associations. For ibuprofen, the dominant organization is found to be composed of small hydrogen bonding aggregates corresponding to cyclic dimers through the carboxyl group. For ketoprofen, the propensity of cyclic dimers is significantly reduced by the formation of hydrogen bonds with the ketone oxygen of the molecule altering the hydrogen bond (HB) associating structures that can be formed and thus molecular dynamics. The issue of the presence/absence of the peculiar low frequency Debye-type process in dielectric relaxation spectroscopy (DRS) data in these materials is addressed. Results obtained from simulations confirm that the Debye process originates from the internal cis-trans conversion of the --COOH carboxyl group. It is shown that the specific intermolecular HB structures associated to a given profen control the main dynamical features of this conversion, in particular its separation from the a-process, which make it detectable or not from DRS. For ibuprofen, the possible role of the --CCCO torsion motion, more "local" than the --COOH motion since it is less influenced by the intermolecular HBs, is suggested in the microscopic origin of the quite intense secondary -relaxation process detected from DRS. [ABSTRACT FROM AUTHOR]

The magnetism of a Fe20Ni80/Cu/Co spin valve, in which a layer of FeNi containing a head-to-head transverse domain wall is coupled to a uniformly magnetized Co layer, via a nonmagnetic Cu layer, was investigated by micromagnetics (mainly numerical simulations). In equilibrium, due to the magnetostatic coupling between the layers, a quasiwall is created in the Co layer, which affects the domain wall profile in the FeNi layer. The dynamics of the domain wall under an applied field is also modified, and two opposite effects due to the spin valve geometry have been found, resulting, on the one hand, from the variation in the width of the domain wall and, on the other hand, from the additional damping of magnetization dynamics due to the cobalt layer. [ABSTRACT FROM AUTHOR]

Presents a study that focused on the magnetization processes in amorphous sandwiches. Preparation of samples using direct current triode sputtering; Association of the creation or annihilation of planar Bloch walls parallel to the surface with magnetic transitions; Magnetic properties of the amorphous sandwiches.

This paper reports numerical investigation, using SCAPS-1D program, of the influence of Cu2ZnSnS4 (the so-called CZTS) material features such as thickness, holes, and defects densities on the performances of ZnO:Al/i-ZnO/CdS/CZTS/Mo solar cells structure. We found that the electrical parameters are seriously affected, when the absorber thickness is lower than 600 nm, mainly due to recombination at CZTS/Molybdenum interface that causes the short-circuit current density loss of 3.6 mA/cm2. An additional source of recombination, inside the absorber layer, affects the short-circuit current density and produces a loss of about 2.1 mA/cm2 above this range of absorber thickness. The J-V characteristic shows that the performance of the device is also limited by a double diode behavior. This effect is reduced when the absorber layer is skinny. Our investigations showed that, for solar cells having a CZTS absorber layer of thin thickness and high-quality materials (defects density ~1015 cm−3), doping less than 1016 cm−3 is especially beneficial. Such CZTS based solar cell devices could lead to conversion efficiencies higher than 15% and to improvement of about 100 mV on the open-circuit voltage value. Our results are in conformity with experimental reports existing in the literature. [ABSTRACT FROM AUTHOR]

This paper reports numerical investigation, using SCAPS-1D program, of the influence of Cu2ZnSnS4 (the so-called CZTS) material features such as thickness, holes, and defects densities on the performances of ZnO:Al/i-ZnO/CdS/CZTS/Mo solar cells structure. We found that the electrical parameters are seriously affected, when the absorber thickness is lower than 600 nm, mainly due to recombination at CZTS/Molybdenum interface that causes the short-circuit current density loss of 3.6 mA/cm². An additional source of recombination, inside the absorber layer, affects the short-circuit current density and produces a loss of about 2.1mA/cm² above this range of absorber thickness. The J-V characteristic shows that the performance of the device is also limited by a double diode behavior. This effect is reduced when the absorber layer is skinny. Our investigations showed that, for solar cells having a CZTS absorber layer of thin thickness and high-quality materials (defects density ~015 cm-3), doping less than 1016 cm-3 is especially beneficial. Such CZTS based solar cell devices could lead to conversion efficiencies higher than 15% and to improvement of about 100mV on the open-circuit voltage value. Our results are in conformity with experimental reports existing in the literature. [ABSTRACT FROM AUTHOR]

In this paper, a systematic study of the electronic, optical, thermodynamic, optoelectronic, and nonlinear optical properties with RHF, B3LYP, wB97XD and BPBE methods using the cc-pVDZ basis set have been described to investigate the influence of fluorine (F) atom, which is an electron donor, on the circumanthracene (C 40 H 16 ). Global reactivity descriptors, hole and electron transport properties were also calculated and compared with other studies on the same molecule. DFT/B3LYP results show that the undoped C 40 H 16 molecule (Egap = 2.135 eV) and its fluorine-doped derivatives (C 40 F 16 and C 40 H 10 F 6 ) are semiconducting materials. However, doping the C 40 H 16 molecule with the fluorine atom, partially or totally, favors the creation of a strong donor-acceptor system by considerably reducing its energy gap (Egap). The energy gap values of molecules doped using DFT/B3LYP method are 2.020 eV and 2.081 eV for the C 40 F 16 and C 40 H 10 F 6 molecules, respectively. These gap energies are below 3 eV, which favours the electronic properties of these molecules. They can be used to design organic solar cells. The nonlinear optical parameters were calculated and compared with those of urea. The values of βmol and μ calculated for C 40 F 16 and C 40 H 10 F 6 are higher than those of urea; this shows that these two materials have good nonlinear optical properties and therefore, are very good candidates for the design of optoelectronics and photonics devices. Futhermore, our results show that the perfluorination effect on the circumanthracene molecule increases the hole and electron reorganization energies, the vertical and adiabatic electron affinities and ionization energies, the optoelectronic and nonlinear optical properties, the transition excitation energy and the reactivity indices. The reorganization energies values suggest that these materials have promising transport properties. The natural bond orbital (NBO) analysis was also performed to determine the stability energy and charge delocalization in molecules. The theoretical results of the compounds studied in our work are in agreement with the experimental results. This confirms their molecular structures., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Density functional theory (DFT) calculations of the antimalarial drug dihydroartemisinin (DHA) functionalized on the carbon nanotube (CNT) were carried out in gas phase and in solution to investigate the role of fCNTs as a nanovector for the targeted delivery of the DHA drug and to predict their chemical descriptors and electronic and nonlinear optical (NLO) properties. The results of the geometric optimization indicate that the functionalization does not change the molecular structure of DHA. Based on our findings of binding and solvation energies, two energetically stable configurations were identified in 1st (fCNT1-2) and 2nd (2fCNT1-2) functionalization. For these stable configurations, the energy gap value goes from 1.52 eV for the (5,5) single wall pristine CNT to 1.27 eV for the 1st functionalization and to 1.06 eV for the 2nd functionalization regardless of the considered media; which gives these nanostructures excellent semiconductor properties. Findings from global reactivity descriptors show that the reactivity of the functionalized CNT is strongly improved in solvent media and that the stability of DHA decreases while its reactivity increases during the functionalization. Thus, the fundamental gap (E f ) in gas phase decreases from 3.65 eV for the virgin CNT to 3.30 eV for fCNT2 and to 3.02 eV for 2fCNT2. On the contrary, in water E f goes from 1.20 eV for the virgin CNT to 0.95 eV for fCNT2 and to 0.74 eV for 2fCNT2; demonstrating an improvement in the reactivity of our fCNTs as nanovectors for targeted delivery of DHA drug. Finally, our findings show that these nanostructures may also have good NLO properties and can be promising materials for NLO applications., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Standard MAPbI 3 (MAPI) perovskite suffers from stability and toxicity problems. In this numerical simulation study using SCAPS-1D software, we propose a hybrid perovskite (MA 1- x FA x Pb 1- y Sr y I 3 ) to reduce these effects; thus, the influence of the mixture of formamidinium (NH 2 CHNH 2 + (FA + )), strontium (Sr), methylammonium (CH 3 NH 2 + (MA + )) and lead (Pb) on the electrical parameters of a hybrid perovskite-based solar cell is studied. This simulation was performed through modeling the perovskite absorber band gap depending on x and y proportions. This mixture leads to increase the crystallinity or stability by decreasing MA + proportion by FA + , while the toxicity is reduced by decreasing Pb 2+ proportion by Sr 2+ . We show that the substitution of 90% MA and 15% Pb (MA 0.1 FA 0.9 Pb 0.85 Sr 0.15 I 3 ) to the standard MAPI radically changes the electrical parameters of the material and the performance of the solar cell. A maximum efficiency of 29% ( J s c = 24.2 mA/cm 2 , V o c = 1.37 V, F F = 87.49 %) is obtained in this simulation of the hybrid perovskite-based solar cell. These results are obtained after optimizing the hybrid perovskite band gap (Eg = 1.60 eV), layer thicknesses (0.400 μm for hybrid perovskite, 0.250 μm for TiO 2 ETL, and 0.150 μm for Cu 2 O HTL), absorber bulk defect density (10 13 cm -3 ), and perovskite/TiO 2 interface defects density (10 12 cm -2 ). Our results show that the composition of MA, FA, Pb, and Sr in the MA 1- x FA x Pb 1- y Sr y I 3 hybrid perovskite may be a way to obtain new perovskites with interesting physical properties for application in solar cells., Competing Interests: The authors declare no conflict of interest., (© 2022 The Author(s).)

In this study, the RHF, B3LYP and wB97XD methods with cc-pVDZ basis set have been used to investigate the influence of carbon atoms substitution with boron atoms on the non-linear optical, electronic, optoelectronic and thermodynamic properties of BEDT-TTF ( C 10 H 8 S 8 ). The results show that the undoped molecule denoted BEDT-TTF or ET (Eg = 3.88 eV) and its derivatives are semi-conductors materials. However, doping C 10 H 8 S 8 with both 3B and 2B, creating a strong donor-acceptor system and considerably improves its energies gap (Egap). The Eg values of these doped molecules are between 2.2 and 2.39 eV less than 3 eV, which makes more interesting electronic properties. The nonlinear optical parameters such as dipole moment (μ), average polarizability ˂α˃ and first-order hyperpolarizability ( β m o l ) have been calculated and compared with the corresponding values of Urea used as prototypical material to study the NLO properties of the compound. These values obtained indicate that these materials exhibit good nonlinear optical properties. Moreover, we have also computed the chemical softness ( ς ) , ionization potential (IP), electron affinity (AE), global hardness (η), refractive index (n), dielectric constant (ε), electric field (E) and electric susceptibility (χ), total electronic energy (Eo), enthalpy H, entropy S. These results indicate that these new materials doped with boron are promising candidates for the construction of optoelectronics and photonic devices., Competing Interests: The authors declare no conflict of interest., (© 2021 The Authors.)

Density functional theory (DFT) was performed in order to predict the structural, chemical descriptors and optoelectronic properties of the drugs Hydroxychloroquine and Azithromycin using the wB97XD, O3LYP and B3LYP functional with 6-31+G(d,p) basis set. It is observed from our studies that most of the descriptors presented show association with some processes, including absorption, blood-brain barrier transport, binding and even toxicity. Hence, the treatment of COVID-19 using Hydroxychloroquine and Azithromycin in some patients as single dose and their combination in patients with Corona virus resistance can be more effective. Our results show that these therapeutic molecules may also have good nonlinear optical applications, may have semiconductor character with wide band gap and can also be promising materials in the production of optoelectronic devices. The density of states and thermodynamic properties were equally determined., (© 2020 The Authors.)