Linker Unit Modification of Triphenylamine-Based Organic Dyes for Efficient Cobalt Mediated Dye-Sensitized Solar Cells

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• 作者：Hanna Ellis ; Susanna K. Eriksson ; Sandra M. Feldt ; Erik Gabrielsson ; Peter W. Lohse ; Rebecka Lindblad ; Licheng Sun ; H氓kan Rensmo ; Gerrit Boschloo ; Anders Hagfeldt
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：October 17, 2013
• 年：2013
• 卷：117
• 期：41
• 页码：21029-21036
• 全文大小：335K
• 年卷期：v.117,no.41(October 17, 2013)
• ISSN：1932-7455

文摘

Linker unit modification of donor-linker-acceptor-based organic dyes was investigated with respect to the spectral and physicochemical properties of the dyes. The spectral response for a series of triphenylamine (TPA)-based organic dyes, called LEG1鈥?, was shifted into the red wavelength region, and the extinction coefficient of the dyes was increased by introducing different substituted dithiophene units on the 蟺-conjugated linker. The photovoltaic performance of dye-sensitized solar cells (DSCs) incorporating the different dyes in combination with cobalt-based electrolytes was found to be dependent on dye binding. The binding morphology of the dyes on the TiO₂ was studied using photoelectron spectroscopy, which demonstrated that the introduction of alkyl chains and different substituents on the dithiophene linker unit resulted in a larger tilt angle of the dyes with respect to the normal of the TiO₂-surface, and thereby a lower surface coverage. The good photovoltaic performance for cobalt electrolyte-based DSCs found here and by other groups using TPA-based organic dyes with a cyclopentadithiophene linker unit substituted with alkyl chains was mainly attributed to the extended spectral response of the dye, whereas the larger tilt angle of the dye with respect to the TiO₂-surface resulted in less efficient packing of the dye molecules and enhanced recombination between electrons in TiO₂ and Co(III) species in the electrolyte.