title: Theoretical study of novel azo-tetraphenylporphyrins: potential photovoltaic materials.
abstract: A density functional theory study was performed to analyze the electron donor-acceptor properties of the cis and trans isomers of a novel azobenzene-containing tetraphenylporphyrin (TPPN2PhC14H29) with different substituents (Br or TMS). In general, the trans isomers are better electron acceptors than the correspondent cis homologues. Their UV-vis spectra were also obtained and a comparison with available experimental results is included. According to these results, the azo compounds reported here are promising materials for the elaboration of dye-sensitized solar cells because their HOMO-LUMO gaps are close to 2 eV. Moreover, the energy of the high intensity absorption bands also fulfills the requirements needed for the operation of a solar cell built with TiO2 and the I(-)/I3(-) pair.
authors.affiliation: Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México , Circuito Exterior SN. Ciudad Universitaria, C.P. 04510 Coyoacán, Mexico City, Mexico.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Hernandez-Marin
authors.forename: Carolina
authors.initials: C
authors.lastname: Caicedo
authors.forename: Ernesto
authors.initials: E
authors.lastname: Rivera
authors.forename: Ana
authors.initials: A
authors.lastname: Martínez