title: Tuning the Electron-Transport and Electron-Accepting Abilities of Dyes through Introduction of Different π-Conjugated Bridges and Acceptors for Dye-Sensitized Solar Cells.
abstract: A series of dyes, containing thiophene and thieno[3,2-b]thiophene as π-conjugated bridging units and six kinds of groups as electron acceptors, were designed for dye-sensitized solar cells (DSSCs). The ground- and excited-state properties of the designed dyes were investigated by using density functional theory (DFT) and time-dependent DFT, respectively. Moreover, the parameters affecting the short-circuit current density and open-circuit voltage were calculated to predict the photoelectrical performance of each dye. In addition, the charge difference density was presented through a three-dimensional (3D) real-space analysis method to investigate the electron-injection mechanism in the complexes. Our results show that the longer conjugated bridge would inhibit the intramolecular charge transfer, thereby affecting the photoelectrical properties of DSSCs. Similarly, owing to the lowest chemical hardness, largest electron-accepting ability, dipole moment (μnormal ) and the change in the energy of the TiO2conduction band (ΔECB ), the dye with a (E)-3-(4-(benzo[c][1,2,5]thiadiazol-4-yl)phenyl)-2-cyanoacrylic acid (TCA) acceptor group would exhibit the most significant photoelectrical properties among the designed dyes.
authors.affiliation: College of Science, Northeast Forestry University, Harbin, 150040, Heilongjiang, China.
authors.forename: Yuanzuo
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Science, Northeast Forestry University, Harbin, 150040, Heilongjiang, China.
authors.forename: Chaofan
authors.initials: C
authors.lastname: Sun
authors.affiliation: Department of Physics, Liaoning University, Shenyang, 110036, Liaoning, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Song
authors.affiliation: Department of Physics, Liaoning University, Shenyang, 110036, Liaoning, China.
authors.forename: Fengcai
authors.initials: F
authors.lastname: Ma
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Yang
keywords: UV/Vis absorption spectra; chemical reactivity parameters; density functional theory; dye-sensitized solar cells; reorganization energy