3,4-Ethylenedioxythiophene (EDOT) and 3,4-ethylenedithiathiophene (EDTT) as terminal blocks for oligothiophene dyes for DSSCs
Thiophene pentamers with a cyanoacrylic acid anchoring group at one end and 3,4-ethylenedioxythiophene (EDOT) or 3,4-ethylenedithiathiophene (EDTT) units at the other end have been synthesized. Preliminary evaluation in DSSCs with a iodide/triiodide liquid electrolyte shows that in spite of the very close electronic properties of the two dyes, replacing EDOT by EDTT leads to a noticeable improvement of conversion efficiency under simulated solar light.
Demeter, Dora,Melchiorre, Fabio,Biagini, Paolo,Jungsuttiwong, Siriporn,Po, Riccardo,Roncali, Jean
Design of organic semiconductors: Tuning the electronic properties of π-conjugated oligothiophenes with the 3,4-ethylenedioxythiophene (EDOT) building block
Hybrid oligothiophenes based on a various combinations of thiophene and 3,4-ethylenedioxythiophene (EDOT) groups have been synthesized. UV/Vis absorption spectra show that the number and relative positions of the EDOT groups considerably affect the width of the HOMO-LUMO gap and the rigidity of the conjugated system. Analysis of the crystallographic structure of two hybrid quaterthiophenes confirms that insertion of two adjacent EDOT units in the middle of the molecule leads to a self-rigidification of the conjugated systems by intramolecular S...O interactions. Cyclic voltammetry data shows that the first oxidation potential of the oligomers decreases with increasing chain length and increasing number of EDOT groups for a given chain length. Electrochemical studies and theoretical calculations show that the positions of the EDOT units in the conjugated chain control the potential difference (ΔEp) between the first and second oxidation steps. Moving the EDOT groups from the outer to the inner positions of the conjugated system increases ΔEp. Theoretical calculations confirm that this phenomenon reflects an increase of the intramolecular coulombic repulsion between positive charges in the dication. A thin-film field-effect transistor was fabricated by vacuum sublimation of a pentamer with alternating thiophene-EDOT structure, and the hole mobility was determined.
Turbiez, Mathieu,Frre, Pierre,Allain, Magali,Videlot, Christine,Ackermann, Joerg,Roncali, Jean
Organic dye for a dye-sensitized solar cell (DSSC) comprising at least one electron-acceptor unit and at least one π-conjugated unit. Said organic dye is particularly useful in a dye-sensitized photoelectric transformation element which, in its turn, can be used in a dye-sensitized solar cell (DSSC).
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Paragraph 0131; 0136
(2016/10/04)
Stable and soluble oligo(3,4-ethylenedioxythiophene)s end-capped with alkyl chains
The synthesis of a new series of stable and soluble EDOT oligomers end-capped with n-hexyl groups is described. Optical and electrochemical results indicate that the synergy between the direct electron-releasing effects of the ethylenedioxy groups and the self-rigidification resulting from intramolecular interactions controls to a large extent the HOMO-LUMO gap.
Turbiez, Mathieu,Frere, Pierre,Roncali, Jean
p. 5357 - 5360
(2007/10/03)
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