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Appunti di Fisica ‘10 18 marzo ore 15.30, aula A Dip. di Fisica della Materia e Ingegneria Elettronica DFT characterization of molecular properties of pigments relevant to dye-sensitized solar cells Dr. Alessandro Sinopoli Dyes sensitized solar cells (DSSCs) are devices devoted to the conversion of solar energy into electricity based on a large band gap nanocrystalline semiconductor sensitized by a dye which is chemically linked to the semiconductor surface and has substantial absorption in the visible range. Only little is known about dye-sensitizers molecular properties relevant to the electron injection process. Ground state geometries, electronic transition energies, and oxidation potentials of several natural and artificial sensitizers are reported here. The HOMO->LUMO transition describes all lowest singlet excited states. The computed alignments of the molecular orbitals of the different molecules, with the band edges of a model TiO2 nanoparticle, provide additional insights into electronic factors governing the efficiency of dye-sensitized solar cell devices. Finally we report on several applications of Density Functional Theory to simulate IR or Raman spectra, electron densities or structural properties.