Jesús Baldenebro-López

Density Functional Theory (DFT) Study of Triphenylamine-Based Dyes for Their Use as Sensitizers in Molecular Photovoltaics

In this work we studied three dyes which are proposed for potential photovoltaic applications and named Dye7, Dye7-2t and Dye7-3t. The Density Functional Theory (DFT) was utilized, using the M05-2X hybrid meta-GGA functional and the 6–31+G(d,p) basis set. This level of calculation was used to find the optimized molecular structure and to predict the main molecular vibrations, the absorption and emission spectra, the molecular orbitals energies, dipole moment, isotropic polarizability and the chemical reactivity parameters that arise from Conceptual DFT. Also, the pKa values were calculated with the semi-empirical PM6 method.

Computational Molecular Nanoscience Study of the Properties of Copper Complexes for Dye-Sensitized Solar Cells

In this work, we studied a copper complex-based dye, which is proposed for potential photovoltaic applications and is named Cu (I) biquinoline dye. Results of electron affinities and ionization potentials have been used for the correlation between different levels of calculation used in this study, which are based on The Density Functional Theory (DFT) and time-dependent (TD) DFT. Further, the maximum absorption wavelengths of our theoretical calculations were compared with the experimental data. It was found that the M06/LANL2DZ + DZVP level of calculation provides the best approximation. This level of calculation was used to find the optimized molecular structure and to predict the main molecular vibrations, the molecular orbitals energies, dipole moment, isotropic polarizability and the chemical reactivity parameters that arise from Conceptual DFT.

Synthesis, structure, characterization and photophysical properties of copper(I) complexes containing polypyridyl ligands

Two novel photoluminescent copper(I) complexes having the compositions [CuI(L1)(PPh3)2]NO3·3CHCl3(1) and [CuI(L2)(PPh3)2]NO3·H2O(2) with PPh3 = triphenylphosphine, L1 = cis-(±)-2-(2,5-di(pyridin-2-yl)-4,5-dihydro-1H-imidazol-4-yl)pyridine and L2 = 2,4,6-tris(2-pyridyl)triazine have been successfully synthesized and characterized by IR and 1H-NMR spectroscopy, FAB+ mass spectrometry and single-crystal X-ray diffraction analysis. Both complexes showed interesting photophysical properties, which were studied experimentally in solution and in the solid state by UV-Vis and fluorescence spectroscopy and theoretically using TD-DFT calculations.

Comparison of several protocols for the computational prediction of the maximum absorption wavelength of chrysanthemin

UV-Vis spectra were calculated using time-dependent density functional theory for the chrysanthemin pigment, which is used as natural dye in dye sensitized solar cells. To this end, we studied four different calculation protocols in order to obtain the best approximation according to the maximum absorption wavelength (λmax) of the experimental spectrum. Furthermore, the optimized geometry, highest occupied molecular orbitals, lowest unoccupied molecular orbitals and electron density were calculated and analyzed. Several chemical models were used with and without the presence of the chlorine atom: the chosen functionals, B3LYP, PBE0 and the M06 family, represent various approximations with different fractions of Hartree-Fock exchange energy. These functionals were combined with the 6–31 + G (d), 6–311 + G (d) and the MIDIX + basis sets. All of these calculation protocols proved a good option, though the B3LYP/MIDIX + chemistry model was the best for predicting the λmax value, using the equilibrium calculation protocol (M1a) in the presence of chlorine.

Theoretical Study of the π-Bridge Influence with Different Units of Thiophene and Thiazole in Coumarin Dye-Sensitized Solar Cells

Eight coumarin derivative dyes were studied by varying the π-bridge size with different thiophene and thiazole units for their potential use in dye-sensitized solar cells (DSSC). Geometry optimization, the energy levels and electron density of the Highest Occupied Molecular Orbital and the Lowest Unoccupied Molecular Orbital, and ultraviolet-visible absorption spectra were calculated by Density Functional Theory (DFT) and Time-Dependent-DFT. All molecular properties were analyzed to decide which dye was the most efficient. Furthermore, chemical reactivity parameters, such as chemical hardness, electrophilicity index, and electroaccepting power, were obtained and analyzed, whose values predicted the properties of the dyes in addition to the rest of the studied molecular properties. Our calculations allow us to qualitatively study dye molecules and choose the best for use in a DSSC. The effects of π-bridges based on thiophenes, thiazoles, and combinations of the two were reviewed; dyes with three units mainly of thiazole were chosen as the best photosensitizers for DSSC.

Theoretical Study of Copper Complexes: Molecular Structure, Properties, and Its Application to Solar Cells

We present a theoretical investigation of copper complexes with potential applications as sensitizers for solar cells. The density functional theory (DFT) and time-dependent DFT were utilized, using the M06 hybrid meta-GGA functional with the LANL2DZ (D95V on first row) and DZVP basis sets. This level of calculation was used to find the optimized molecular structure, the absorption spectra, the molecular orbitals energies, and the chemical reactivity parameters that arise from conceptual DFT. Solvent effects have been taken into account by an implicit approach, namely, the polarizable continuum model (PCM), using the nonequilibrium version of the IEF-PCM model.

Computational study of the influence of the π-bridge conjugation order of novel molecular derivatives of coumarins for dye-sensitized solar cells using DFT

Abstract Three novel molecules derived from D-π-A type coumarin were studied in order to be considered as potential dyes in dye-sensitized solar cells (DSSC), using density functional theory (DFT) and time-dependent density functional theory (TD-DFT). M06 and M06-2X density functionals were chosen and combined with the 6-31G(d) basis set. The effect of the π-bridge was studied using two units of methyl thiophene and one unit of dimethyl cyclopentadithiophene in different conjugation order. Geometry optimization, and the highest occupied molecular orbital and lowest unoccupied molecular orbital density and energy levels, and maximum absorption wavelength were calculated. Besides, certain chemical reactivity parameters, such as chemical hardness (η), electrophilicity index (ω), electrodonating power (ω−), and electroaccepting power (ω+), were obtained. All these calculations were analyzed taking into account the potential application of the proposed molecular systems as photosensitizers in DSSC. The results suggest that the three proposed molecules are highly efficient dyes.

Synthesis, crystal structure, DFT studies and photophysical properties of a copper(I)–tri­phenyl­phosphane complex based on trans-(±)-2,4,5-tris­(pyridin-2-yl)-2-imidazoline

The possibility of using less expensive and nontoxic metals, such as copper, as substitutes for more expensive heavy metals in the synthesis of new transition-metal complexes to be used as sensitizers in dye-sensitized solar cells (DSSCs) has stimulated research in this field. The novel photoluminescent copper(I) complex bis(triphenylphosphane-κP)[trans-(±)-2,4,5-tris(pyridin-2-yl)-2-imidazoline-κ2N2,N3]copper(I) hexafluorophosphate, [CuI(C18H15N5)(C18H15P)2]PF6, has been successfully synthesized and characterized by IR and 1H NMR spectroscopy, as well as by single-crystal X-ray diffraction and thermogravimetric analysis. The complex showed interesting photophysical properties, which were studied experimentally in solution and in the solid state by UV-Vis and fluorescence spectroscopy. Density functional theory (DFT) calculations with dichloromethane as solvent reproduced reasonably well the HOMO and LUMO orbitals of the title compound.

Quantum chemical study of the effect of π-bridge on the optical and electronic properties of sensitizers for DSSCs incorporating dioxythiophene and thiophene units

Abstract Twelve molecules were theoretically studied through density functional theory with the M06 density functional and the 6-31G(d) basis set. The molecular systems have potential application as sensitizers for dye-sensitized solar cells; these molecular structures are composed of triphenylamine as the donor moiety, different conjugation orders of thiophene and dioxythiophene as the π-bridge, and cyanoacrylic acid as the acceptor moiety. This study focused on the effect of the π-bridge on the properties of interest. Ground-state geometry optimization, the highest occupied molecular orbital, the lowest unoccupied molecular orbital, and their energy levels were calculated and analyzed. Absorption wavelengths, vertical energy, oscillator strength, and electron transitions were calculated through time-dependent density functional theory with the M06-2X and CAM-B3LYP functionals using the 6-31G(d) basis set. Driving force of injection (ΔGinj) was calculated and analyzed from the ground-state oxidation potential of the dye and the energy associated with the maximum absorption wavelength. As an important element presented in this study, chemical reactivity parameters are discussed, such as chemical hardness, electrodonating power, electroaccepting power, and electrophilicity index. In conclusion, a reliable methodology was presented and discussed to predict properties in triphenylamine derivative dyes considering the modification of the π-bridge.

Computational characterization of the molecular structure and properties of Dye 7 for organic photovoltaics.

Organic dyes have great potential for its use in solar cells. In this recent work, the molecular structure and properties of Dye 7 were obtained using density functional theory (DFT) and different levels of calculation. Upon comparing the molecular structure and the ultraviolet visible spectrum with experimental data reported in the literature, it was found that the M05-2X/6-31G(d) level of calculation gave the best approximation. Once the appropriate methodology had been obtained, the molecule was characterized by obtaining the infrared spectrum, dipole moment, total energy, isotropic polarizability, molecular orbital energies, free energy of solvation in different solvents, and the chemical reactivity sites using the condensed Fukui functions.