title: Electronic structures and absorption properties of three kinds of ruthenium dye sensitizers containing bipyridine-pyrazolate for solar cells.
abstract: The geometries, electronic structures and the electronic absorption spectra of three kinds of ruthenium complexes, which contain tridentate bipyridine-pyrazolate ancillary ligands, were studied using density functional theory (DFT) and time-dependent DFT. The calculated results indicate that: (1) the strong conjugated effects are formed across the pyrazoalte-bipyridine groups; (2) the interfacial electron transfer between electrode and the dye sensitizers is an electron injection processes from the excited dyes to the conduction band of TiO2; (3) the absorption bands in visible region have a mixed character of metal-to-ligand charge transfer and ligand-to-ligand charge transfer, but the main character of absorption bands near UV region ascribe to π→π* transitions; (4) introducing pyrazolate and -NCS groups are favorable for intra-molecular charge transfer, and they are main chromophores that contribute to the sensitization of photon-to-current conversion processes, but introducing -Cl and the terminal group -CF3 are unfavorable to improve the dye performance in dye sensitized solar cells.
authors.affiliation: State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials, Department of Applied Physics, Lanzhou University of Technology, Lanzhou, Gansu 730050, China. zhcrlut@126.com
authors.forename: Cai-Rong
authors.initials: CR
authors.lastname: Zhang
authors.forename: Zi-Jiang
authors.initials: ZJ
authors.lastname: Liu
authors.forename: Yi-Tong
authors.initials: YT
authors.lastname: Sun
authors.forename: Yu-Lin
authors.initials: YL
authors.lastname: Shen
authors.forename: Yu-Hong
authors.initials: YH
authors.lastname: Chen
authors.forename: Yan-Jun
authors.initials: YJ
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Hai-Ming
authors.initials: HM
authors.lastname: Zhang
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D000042:Absorption; D004396:Coloring Agents / Q000737:chemistry*; D004583:Electrons; D008958:Models, Molecular; D017319:Photosensitizing Agents / Q000737:chemistry*; D011720:Pyrazoles / Q000737:chemistry*; D011789:Quantum Theory; D017975:Ruthenium Compounds / Q000737:chemistry*; D012993:Solar Energy; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
chemical_list: D004396:Coloring Agents; D017319:Photosensitizing Agents; D011720:Pyrazoles; D017975:Ruthenium Compounds; C031280:pyrazole; D015082:2,2'-Dipyridyl