Molecular dynamic simulation of structural- electronic characteristics and spectral properties of dyes and solutions based on them for DSSC ; Simulation de la dynamique moléculaire des caractéristiques structurelles et électroniques et des propriétés spectrales des colorants utilisés dans les cellules solaires

The objective of this thesis is on the one hand to analyze the electronic properties of several dye models that can potentially be used in solar cells and on the other hand to characterize the effect of the solvent on the local structure of the dye D205 in solution and at the TiO2 interface. These investigations were carried out using quantum chemistry and molecular dynamics (MD) simulation calculations.In the first chapter of the thesis we tried to solve two problems important for describing and predicting the spectral properties of dyes for DSSCs. It was shown that the Time-Dependent DFT (TDDFT) approximation with a combination of B3LYP and CAM-B3LYP (or M06-2X) functionals with the 6-31++G(d,p) basis set can be recommended for the prediction of dye absorption spectra. We also proposed an algorithm to predict new molecular structures with improved electron spectral parameters and predicted the structure of three new dyes for DSSC.In the second part of the thesis we analyzed the effect of the composition of the D205/Acetonitrile/BmimBF4 dye mixture. D205 is an organic dye used in solar cells. To perform this analysis, we performed quantum chemical calculations to parameterize the intramolecular part of the D205 dye force field. The charges describing the ground state and excited state of the D205 dye were also determined while the Lennard-Jones parameters were taken from the OPLS(AA) library. Radial nearest neighbor distribution functions were used to characterize the environment around the donor, acceptor, bridge and butyl chain moieties of the D205 dye in the ground and excited states.In the third part of this thesis joint molecular dynamics (MD) simulations and density functional theory (DFT) calculations were used to study the structure and dynamics of an indoline dye D205 anchored at the solid˗liquid interface of small TiO2 anatase nanoparticles in admixture with solvents such as acetornitrile , and 1-butyl-3-methylimidazolium-based ionic liquids with hexapluorophate and trifluoromethanesulfonate anions. ...