title: Substituent effect on the π linkers in triphenylamine dyes for sensitized solar cells: a DFT/TDDFT study.
abstract: A series of metal-free organic donor-π bridge-acceptor dyes are studied computationally using density functional theory (DFT) and time-dependent DFT (TDDFT) approaches to explore their potential performances in dye-sensitized solar cells (DSSCs). Taking triphenylamine (TPA) and cyanoacrylic acid moieties as donor and acceptor units, respectively, the effects of different substituents of the π linkers in the TPA-based dyes on the energy conversion efficiency of the DSSCs are theoretically evaluated through optimized geometries, charge distributions, electronic structures, simulated absorption spectra, and free energies of injection. The results show that the molecular orbital energy levels and electron-injection driving forces of the TPA dyes can be tuned by the introduction of substituents with different electron-withdrawing or -donating abilities. The electron-withdrawing substituent always lowers the energies of both frontier orbitals, while the electron-donating one heightens them simultaneously. The efficiency trend of these TPA derivatives as sensitizers in DSSCs is also predicted by analyzing the light-harvesting efficiencies and the free energies of injection. The following substituents are shown to increase the efficiency of the dye: OMe, OEt, OHe, and OH.
authors: College of Materials Science and Engineering, Wuhan Textile University, 430073 Wuhan, China. xujie0@ustc.edu
authors: Jie
authors: J
authors: Xu
authors: Ligen
authors: L
authors: Zhu
authors: Dong
authors: D
authors: Fang
authors: Biao
authors: B
authors: Chen
authors: Li
authors: L
authors: Liu
authors: Luoxin
authors: L
authors: Wang
authors: Weilin
authors: W
authors: Xu
mesh_terms: D000588:Amines / Q000737:chemistry*; D003487:Cyanoacrylates / Q000737:chemistry; D011211:Electric Power Supplies; D005456:Fluorescent Dyes / Q000737:chemistry*; D015394:Molecular Structure; D011789:Quantum Theory; D013997:Time Factors
chemical_list: D000588:Amines; D003487:Cyanoacrylates; D005456:Fluorescent Dyes