Impact of doping with organic dopants and mixed doping with alkali metals and organic dopants on the absorption, electronic, optoelectronic, thermodynamic and nonlinear optical properties of dibenzo[b,def]chrysene in gaseous media: DFT and TD-DFT studies.

CONTEXT: In this study, we evaluate the geometrical, absorption, optoelectronic, electronic, nonlinear optical (NLO) and thermodynamic properties of dibenzo[b,def]chrysene molecule derivatives by means of DFT and TD-DFT simulations. In view of the aim of producing new high-performance materials for non-linear optics (NLO) by doping test, two types of doping were used. We obtained six derivatives by doping with organic dopants (Nitro, amide and ticyanoethenyl) and mixed alkali metal (potassium) and organic dopants. Doping with organic dopants produced molecules A, B and C, respectively when substituting one hydrogen with nitro (NO2), amide (CONH2) and tricyanoethenyl (C5N3) groups, while mixed doping involved considering A, B and C and then substituting two hydrogens with two potassiums to obtain compounds D, E and F respectively. The negative values of the various interaction energies calculated for all the doped molecules show that they are all stable, but also that molecules C and F are the most stable in the case of both dopings. The gap energies calculated at the B3LYP level of theory are all below 3 eV, which means that all the molecules obtained are semiconductors. Better still, compounds C and F, with gap energies of 1.852 eV and 1.204 eV, respectively, corresponding to decreases of 35.67% and 58.18% in gap energy compared with the pristine molecule, are more reactive than the other doped molecules. Mixed doping is therefore a highly effective way of narrowing the energy gap and boosting the semiconducting character and reactivity of organic materials. Optoelectronic properties have also been improved, with refractive index values higher than those of the reference material, glass. This shows that our compounds could be used under very high electric field conditions of the order of 4.164 × 109 V.m-1 for C and 7.410 × 109 V.m-1 for F the highest values at the B3LYP level of theory. The maximum first-order hyperpolarizability values for both types of doping are obtained at the CAM-B3LYP level of theory by C: ß mol = 92.088 × 10-30esu and by F: ß mol = 129.449 × 10-30esu, and second-order values are also given by these same compounds. These values are higher than the reference value, which is urea, making our compounds potential candidates for high-performance NLO applications. In dynamic mode and at a frequency of 1064 nm, at the CAM-B3LYP level of theory, the highest dynamic hyperpolarizability coefficients were obtained by C and F. Hyper-Rayleigh scattering ß HRS , coefficients of the electro-optical Pockel effect (EOPE), EFISHG, third-order NLO-response degree four-wave mixing γ DFWM , quadratic nonlinear refractive index n2 were also calculated. The maximum values of n2 are obtained by C (6.13 × 10-20 m2/W) and F (6.60 × 10-20 m2/W), these values are 2.24 times higher than that of fused silica which is the reference for degenerate four-wave mixing so our molecules could also have applications in optoelectronics as wavelength converters, optical pulse modulators and optical switches. METHODS: Using the DFT method, we were able to determine the optimized and stable electronic structures of doped dibenzo[b,def]chrysene derivatives in the gas phase. We limited ourselves to using the proven B3LYP and CAMB3LYP levels of theory for calculating electronic properties, and non-linear optics with the 6-311G + + (d,p) basis set, which is a large basis set frequently used for these types of compound. Gaussian 09 software was used to run our calculations, and Gauss View 6.0.16 was used to visualize the output files. TD-DFT was also used to determine absorption properties at the B3LYP level of theory, using the same basis set.

Ab-initio and density functional theory (DFT) computational study of the effect of fluorine on the electronic, optical, thermodynamic, hole and electron transport properties of the circumanthracene molecule.

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 (C40H16). 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 C40H16 molecule (Egap = 2.135 eV) and its fluorine-doped derivatives (C40F16 and C40H10F6) are semiconducting materials. However, doping the C40H16 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 C40F16 and C40H10F6 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 ßmol and µ calculated for C40F16 and C40H10F6 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.

Computational study of physicochemical, optical, and thermodynamic properties of 2,2-dimethylchromene derivatives.

CONTEXT: A large number of heterocyclic compounds are used as drugs, mainly due to the duality of lipophilicity playing in hydrophobic interactions and solubility with at least one hydrogen bond acceptor. The study of electronic properties is then important to better understand not only these charge distribution effects but also some other physicochemical properties involved in bioactivity to directly assess the bioavailability of these compounds and a possible classification in related applications. Phytomolecules such as chromenes are very accessible molecules exhibiting a bioactivity. Our study is focused on the impact of a number of functional groups acting on some 2,2-dimethylchromene derivatives, namely their global reactivity from the frontier molecular orbitals and local reactivity from the Fukui functions, where the carbonyl group acting as an electron withdrawal group has the most relevant effect, the solubility from the partition coefficient Log P strongly depending on the charge distribution and electronegative sites, the optical effects from the delocalization in the vinyl group, as well as the evaluation of the entropy associated with the molecular flexibility also acting on the bioactivity. Despite the effects of the wave function or density methods on the order of magnitude of these properties, these compounds are consistent with the rules for a potential oral drug candidate. METHODS: The calculations of the electronic properties were performed through two levels of theory: Hartree-Fock level as a wave function-based method as an ab initio reference including some physically consistent eigenvalues and density functional theory DFT as a correlation consistent method using different functionals: hybrid or with a long-range correction. The basis set used is a 6-311++G(d,p) Pople basis set including diffuse and polarization basis functions. The basis set is adapted to the size of the molecules and consequently to the degree of electronic localization. Gaussian 09 software was used for the computation.

Structural, electronic and nonlinear optical properties, reactivity and solubility of the drug dihydroartemisinin functionalized on the carbon nanotube.

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 (Ef) 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 Ef 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.

Computational analysis of mixed cation mixed halide-based perovskite solar cell using SCAPS-1D software.

Standard MAPbI3 (MAPI) perovskite suffers from stability and toxicity problems. In this numerical simulation study using SCAPS-1D software, we propose a hybrid perovskite (MA1-x FA x Pb1-y Sr y I3) to reduce these effects; thus, the influence of the mixture of formamidinium (NH2CHNH 2 + (FA+)), strontium (Sr), methylammonium (CH3NH 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 Pb2+ proportion by Sr2+. We show that the substitution of 90% MA and 15% Pb (MA0.1FA0.9Pb0.85Sr0.15I3) 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/cm2, 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 TiO2 ETL, and 0.150 µm for Cu2O HTL), absorber bulk defect density (1013 cm-3), and perovskite/TiO2 interface defects density (1012 cm-2). Our results show that the composition of MA, FA, Pb, and Sr in the MA1-x FA x Pb1-y SryI3 hybrid perovskite may be a way to obtain new perovskites with interesting physical properties for application in solar cells.

Ab initio investigation of nonlinear optical, electronic, and thermodynamic properties of BEDT-TTF molecule: doping with boron.

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 ( ß 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.

Determination of the structural, electronic, optoelectronic and thermodynamic properties of the methylxanthine molecules theophylline and theobromine.

RHF and DFT (wB97XD and B3LYP) methods with the 6-31++G** basis set have been used to study structural, optoelectronic and thermodynamic properties of Theophylline and Theobromine. Dipole moment, average polarizability, anisotropy, first-order molecular hyperpolarizability, second-order molecular polarizability, HOMO and LOMO energy gap, molar refractivity, chemical hardness, chemical softness, electronic chemical potential, electronegativity, electrophilicity index, dielectric constant, electric susceptibility, refractive index and their thermodynamic properties have equally been calculated. To understand the vibrational analysis of our system, IR and RAMAN frequencies were calculated and described. Results reveal that molecules can have applications in linear and nonlinear optical devices, photonic devices and in molecular electronics. Equally, from dipole moment, average polarizability, anisotropy, first-order molecular hyperpolarizability, second-order molecular polarizability, HOMO and LOMO energy gap, molar refractivity, chemical hardness, chemical softness, electronic chemical potential, electronegativity, electrophilicity index and literature we suggest that Theophylline and Theobromine be consider as candidates for the treatment of COVID-19 and other respiratory diseases.

Study of the structural, chemical descriptors and optoelectronic properties of the drugs Hydroxychloroquine and Azithromycin.

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.

A comparative study of ibuprofen and ketoprofen glass-forming liquids by molecular dynamics simulations.

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 α-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 γ-relaxation process detected from DRS.