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Title: Nanocarbon counterelectrode for dye sensitized solar cells

Abstract

Nanosize carbon powders were deposited on conducting glass substrate for counterelectrode application in dye sensitized solar cell (DSSC). Electrochemical impedance measurement shows that charge transfer resistance of carbon electrode in liquid electrolyte is 0.74 {omega} cm{sup -2}, which is two times less than that of screen printed platinum. Using such counterelectrode and dye sensitized TiO{sub 2} working electrode, DSSC was fabricated. Under one sun illumination (AM1.5, P{sub in} of 100 mW cm{sup -2}), carbon counterelectrode DSSC shows 6.73% overall energy conversion efficiency with good stability.

Authors:
; ; ;  [1]
  1. Electric and Magnetic Devices Research Group, Korea Electrotechnology Research Institute, Changwon 641-120 (Korea, Republic of)
Publication Date:
OSTI Identifier:
20971882
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 90; Journal Issue: 17; Other Information: DOI: 10.1063/1.2731495; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CARBON; CHARGE EXCHANGE; DYES; ELECTROCHEMISTRY; ELECTRODES; ELECTROLYTES; ENERGY CONVERSION; GLASS; IMPEDANCE; NANOSTRUCTURES; PARTICLES; PLATINUM; POWDERS; SOLAR CELLS; SPECTROSCOPY; SUBSTRATES; TITANIUM OXIDES

Citation Formats

Ramasamy, Easwaramoorthi, Lee, Won Jae, Lee, Dong Yoon, and Song, Jae Sung. Nanocarbon counterelectrode for dye sensitized solar cells. United States: N. p., 2007. Web. doi:10.1063/1.2731495.
Ramasamy, Easwaramoorthi, Lee, Won Jae, Lee, Dong Yoon, & Song, Jae Sung. Nanocarbon counterelectrode for dye sensitized solar cells. United States. doi:10.1063/1.2731495.
Ramasamy, Easwaramoorthi, Lee, Won Jae, Lee, Dong Yoon, and Song, Jae Sung. Mon . "Nanocarbon counterelectrode for dye sensitized solar cells". United States. doi:10.1063/1.2731495.
@article{osti_20971882,
title = {Nanocarbon counterelectrode for dye sensitized solar cells},
author = {Ramasamy, Easwaramoorthi and Lee, Won Jae and Lee, Dong Yoon and Song, Jae Sung},
abstractNote = {Nanosize carbon powders were deposited on conducting glass substrate for counterelectrode application in dye sensitized solar cell (DSSC). Electrochemical impedance measurement shows that charge transfer resistance of carbon electrode in liquid electrolyte is 0.74 {omega} cm{sup -2}, which is two times less than that of screen printed platinum. Using such counterelectrode and dye sensitized TiO{sub 2} working electrode, DSSC was fabricated. Under one sun illumination (AM1.5, P{sub in} of 100 mW cm{sup -2}), carbon counterelectrode DSSC shows 6.73% overall energy conversion efficiency with good stability.},
doi = {10.1063/1.2731495},
journal = {Applied Physics Letters},
number = 17,
volume = 90,
place = {United States},
year = {Mon Apr 23 00:00:00 EDT 2007},
month = {Mon Apr 23 00:00:00 EDT 2007}
}
  • The optical and electronic properties of dye aggregates of p-methyl red on a TiO2 anatase (101) surface were modeled as a function of aggregation order (monomer to pentameric dye) via first principles calculations. A progressive red-shifting and intensity increase toward the visible region in UV/vis absorption spectra is observed from monomeric-to-tetrameric dyes, with each molecule in a given aggregate binding to one of the four possible TiO2 (101) adsorption sites. The pentamer exhibits a blue-shifted peak wave- length in the UV/vis absorption spectra and less absorption intensity in the visible region in comparison; a corresponding manifestation of H-aggregation occurs sincemore » one of these five molecules cannot occupy an adsorption site. This finding is consistent with experiment. Calculated density of states (DOS) and partial DOS spectra reveal similar dye…TiO2 nanocomposite conduction band characteristics but different valence band features. Associated molecular orbital distributions reveal dye-to-TiO2 interfacial charge transfer in all five differing aggregate orders; meanwhile, the level of intramolecular charge transfer in the dye becomes progressively localized around its azo- and electron-donating groups, up to the tetrameric dye/TiO2 species. Dye adsorption energies and dye coverage levels are calculated and compared with experiment. Overall, the findings of this case study serve to aid the molecular design of azo dyes towards better performing DSSC devices wherein they are incorporated. In addition, they provide a helpful example reference for understanding the effects of dye aggregation on the adsorbate…TiO2 interfacial optical and electronic properties.« less
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  • Donor-pi-acceptor dyes containing thiophenyl pi-conjugated units and cyanoacrylate acceptor groups are among the best-performing organic chromophores used in dye-sensitized solar cell (DSC) applications. Yet, the molecular origins of their high photovoltaic output have remained unclear until now. This synchrotron-based X-ray diffraction study elucidates these origins for the high-performance thiophenylcyanoacrylate-based dye MK-2 (7.7% DSC device efficiency) and its molecular building block, MK-44. The crystal structures of MK-2 and MK-44 are both determined, while a high-resolution charge-density mapping of the smaller molecule was also possible, enabling the nature of its bonding to be detailed. A strong S center dot center dot centermore » dot C equivalent to N intramolecular interaction is discovered, which bears a bond critical point, thus proving that this interaction should be formally classified as a chemical bond. A topological analysis of the pi-conjugated portion of MK-44 shows that this S center dot center dot center dot C equivalent to N bonding underpins the highly efficient intramolecular charge transfer(ICT) in thiophenylcyanoacrylate dyes. This manifests as two bipartite ICT pathways bearing carboxylate and nitrile end points. In turn, these pathways dictate a preferred COO/CN anchoring mode for the dye as it adsorbs onto TiO2 surfaces, to form the dye TiO2 interface that constitutes the DSC working electrode. These results corroborate a recent proposal that all cyanoacrylate groups anchor onto TiO2 in this COO/CN binding configuration. Conformational analysis of the MK-44 and MK-2 crystal structures reveals that this S center dot center dot center dot C equivalent to N bonding will persist in MK-2. Accordingly, this newly discovered bond affords a rational explanation for the attractive photovoltaic properties of,MK-2. More generally, this study provides the first unequivocal evidence for an S center dot center dot center dot C equivalent to N interaction, confirming previous speculative assignments of such interactions in other compounds.« less
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