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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/3362
Title: 2,7-diaminofluorene-based organic dyes for dye-sensitized solar cells: Effect of auxiliary donor on optical and electrochemical properties
Authors: Baheti A.
Singh P.
Lee C.-P.
Thomas K.R.J.
Ho K.-C.
Published in: Journal of Organic Chemistry
Abstract: New organic dyes containing a diarylaminofluorene unit as an electron donor and cyanoacrylic acid as acceptor and anchoring group in a donor-Ï€-donor- Ï€-acceptor architecture have been synthesized and characterized as sensitizers for nanocrystalline TiO2-based dye-sensitized solar cells. They have shown three major electronic absorptions originating from the Ï€-Ï€* and charge-transfer transitions covering the broad visible range (250-550 nm) in solution. The charge-transfer transition of the dyes exhibited negative solvatochromism, suggesting a polarized ground state. They have also displayed acidochromism in solution owing to the presence of a protonation-deprotonation equilibrium. On comparison with the triphenylamine and carbazole-based parent dyes (E)-2-cyano-3-(4-(diphenylamino)phenyl)acrylic acid and (E)-2-cyano-3-(9-ethyl-9H-carbazol-3-yl)acrylic acid they exhibited longer wavelength absorptions and facile oxidation, indicating the stronger electron-donating ability of the auxiliary chromophores. In addition, they exhibited nearly two times larger light-to-electron conversion efficiency under simulated AM 1.5 G irradiation (100 mW cm-2) with an aperture mask when compared to the parent dyes. Among the new dyes, the one containing the naphthylphenylamine segment showed better device characteristics attributable to the higher HOMO energy level which probably facilitates the regeneration of the dye and effective suppression of the back reaction of the injected electrons with the I3- in the electrolyte. The optical properties of the dyes were modeled using TDDFT simulations employing different theoretical models (B3LYP, CAM-B3LYP, and MPW1K), and the best correlations with the observed parameters have been found for CAM-B3LYP and MPW1K calculations. The electron lifetimes extracted from the electrochemical impedance measurements of the dye-sensitized solar cells were used to interpret the solar cell efficiency alternations. © 2011 American Chemical Society.
Citation: Journal of Organic Chemistry (2011), 76(12): 4910-4920
URI: https://doi.org/10.1021/jo200501b
http://repository.iitr.ac.in/handle/123456789/3362
Issue Date: 2011
ISSN: 223263
Author Scopus IDs: 26638669500
56311408100
55050004100
57203389297
56962715200
Author Affiliations: Baheti, A., Organic Materials Lab, Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee-247 667, India
Singh, P., Organic Materials Lab, Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee-247 667, India
Lee, C.-P., Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
Thomas, K.R.J., Organic Materials Lab, Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee-247 667, India
Ho, K.-C., Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan
Corresponding Author: Thomas, K. R. J.; Organic Materials Lab, Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee-247 667, India; email: krjt8fcy@iitr.ernet.in
Appears in Collections:Journal Publications [CY]

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