title: Electron-acceptor-dependent light absorption, excited-state relaxation, and charge generation in triphenylamine dye-sensitized solar cells.
abstract: By choosing a simple triphenylamine electron donor, we herein compare the influence of electron acceptors benzothiadiazole benzoic acid (BTBA) and cyanoacrylic acid (CA), on energy levels, light absorption, and dynamics of excited-state evolution and electron injection. DFT and time-dependent DFT calculations disclosed remarkable intramolecular conformational changes for the excited states of these two donor-acceptor dyes. Photoinduced dihedral angle variation occurs to the triphenylamine unit in the CA dye and backbone planarization happens to conjugated aromatic blocks in the BTBA dye. Femtosecond spectroscopic measurements suggested the crucial role of having a long excited-state lifetime in maintaining a high electron-injection yield because a reduced driving force for a low energy-gap dye can result in slower electron-injection dynamics.
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 13002 (PR China).
authors.forename: Renzhi
authors.initials: R
authors.lastname: Li
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Cancan
authors.initials: C
authors.lastname: Yan
authors.forename: Zhaoyang
authors.initials: Z
authors.lastname: Yao
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
mesh_terms: D065638:Absorption, Radiation; D000179:Acrylates / Q000737:chemistry; D000588:Amines / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D011211:Electric Power Supplies; D004579:Electron Transport; D008027:Light; D008958:Models, Molecular; D008968:Molecular Conformation; D012993:Solar Energy; D013830:Thiadiazoles / Q000737:chemistry
chemical_list: D000179:Acrylates; D000588:Amines; D004396:Coloring Agents; D013830:Thiadiazoles; C015700:benzo-1,2,3-thiadiazole; C036658:acrylic acid
keywords: cyclic voltammetry; density functional calculations; dyes/pigments; energy conversion; solar cells