Simple organic molecules bearing a 3,4-ethylenedioxythiophene linker for efficient dye-sensitized solar cells.

Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.
Chemical Communications (Impact Factor: 6.38). 12/2008; DOI: 10.1039/b808535h
Source: PubMed

ABSTRACT 3,4-Ethylenedioxythiophene and bis[2-(2-methoxyethoxy)ethoxy]thiophene bridged donor-acceptor molecules for dye-sensitized solar cells have been synthesized, one of which achieved a solar-to-energy conversion efficiency of 7.3%, compared to 7.7% optimized for N719 dye.

  • [Show abstract] [Hide abstract]
    ABSTRACT: 5,10,15,20-Tetrakis(2,4,6-trimethylphenyl)-6'-carboxylquinoxalino[2,3-b]quinoxalino[12,13-b']porphyrinatozinc(II) (ZnPBQ) is synthesized to evaluate the effects of π elongation of quinoxaline-fused porphyrins on the optical, electrochemical, and photovoltaic properties. ZnPBQ showed an intensified Soret band as well as red-shifted Soret and Q bands relative to 5,10,15,20-tetrakis(2,4,6-trimethylphenyl)-6'-carboxylquinoxalino[2,3-b]porphyrinatozinc(II) (ZnPQ), demonstrating the improved light-harvesting property of ZnPBQ. The optical and electrochemical HOMO-LUMO gaps were consistent with those estimated by DFT calculations. The photovoltaic properties were compared under optimized conditions, in which a sealed device structure with TiCl(4) -treated, TiO(2) double layers was used. The ZnPBQ cell exhibited a relatively high power conversion efficiency (η) of 4.7%, which was smaller than that of the ZnPQ cell (η=6.3%). The weaker electronic coupling between the LUMO of ZnPBQ and conduction band (CB) of TiO(2) or more tilted geometry of ZnPBQ on the TiO(2) surface may result in the low electron injection/charge collection efficiency as well as the low incident photon-to-current efficiency (IPCE) for the ZnPBQ cell (maximum IPCE=56%) relative to the ZnPQ cell (maximum IPCE=75%), leading to the lower η value of the ZnPBQ cell than that of the ZnPQ cell. In addition, the open-circuit potential of the ZnPBQ cell also slightly decreased with the effect of charge recombination from the electrons injected into the CB of TiO(2) to I(3)(-).
    ChemSusChem 06/2011; 4(6):797-805. · 7.48 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: UV-Vis spectra are calculated using time-dependent density functional theory for several organic dyes--4-(N, N-dimethylamino) benzonitrile, alizarin, squaraine, polyene-linker dyes, oligothiophene-containing coumarin dyes (NKX series) and triphenylamine-donor dyes. Most of these dyes (except, for the first two) or their derivatives are considered to be promising organic dyes for dye-sensitized solar cells. An accurate description of the photophysics of such dyes is imperative for understanding and creating better dyes. To this end, we studied the dyes within several approximations to the exchange-correlation functional. The chosen functionals--PBE, M06L, B3LYP, M06, CAM-B3LYP, and wB97--represent the various classes of approximations that are currently being used to study material properties. From amongst the six approximations studied here, CAM-B3LYP outperformed the others in its description of charge-transfer excitations in most (though, not all) of the dyes. This study shows why it is difficult to choose a particular functional a priori, especially when starting out with a new dye for solar cell application. A possible way to judge the fitness of an approximation is used in this work and it is shown to provide a good quantitative guideline for subsequent research in this field.
    The Journal of Chemical Physics 06/2012; 136(22):224301. · 3.12 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Functional organic dyes have promising prospect in dye-sensitized solar cells as a crucial element, of which sensitizers based on donor--acceptor are the most important dyes. On the basis of the structures of the aromatic amine donors such as tri-phenylamine and indoline, this paper reviews the photoelectric conversion properties of organic sensitizers since 2008, and highlights research work in our laboratory in this area.
    Science China-Chemistry 01/2012; 55(5):677-697. · 1.33 Impact Factor

Full-text (2 Sources)

Available from
Aug 6, 2014