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Effect of Auxiliary Chromophores on the Optical, Electrochemical, and Photovoltaic Properties of Carbazole‐Based Dyes
Author(s) -
Venkateswararao A.,
Justin Thomas K. R.,
Lee ChuanPei,
Ho KuoChuan
Publication year - 2015
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.201402235
Subject(s) - homo/lumo , carbazole , chemistry , diphenylamine , photochemistry , chromophore , fluorene , photocurrent , thiophene , moiety , optoelectronics , organic chemistry , polymer , materials science , molecule
Organic dyes containing 2‐diphenylaminocarbazole donors and decorated with auxiliary chromophores at the diphenylamine moiety have been synthesized and characterized. The nature of the chromophores on diphenylamine unit alters the light‐harvesting properties and HOMO/LUMO energies of the dyes. Butoxy substitution raises the HOMO and lowers the LUMO energies. But the incorporation of fluorenyl units fine‐tunes the LUMO upwardly, which improves the thermodynamic driving force for electron injection into the conduction band of TiO 2 and hikes the incident photon‐to‐current conversion efficiency. Consequently, a dye with fluorene in the donor unit and thiophene in the π‐conjugation pathway is the most efficient (5.76 %) and has the highest photocurrent density (14.60 mA cm −2 ) in the series. Electrochemical impedance analysis of the devices showed the importance of fluorene units in suppressing electron recombination.