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International Journal of Photoenergy
Volume 2013, Article ID 159502, 8 pages
http://dx.doi.org/10.1155/2013/159502
Research Article

Characterization of Natural Dye Extracted from Wormwood and Purple Cabbage for Dye-Sensitized Solar Cells

1Graduate Institute of Manufacturing Technology, National Taipei University of Technology, Taipei 10608, Taiwan
2Department of Vehicle Engineering, National Taipei University of Technology, Taipei 10608, Taiwan
3Department of Industrial Design, National Taipei University of Technology, Taipei 10608, Taiwan
4Graduate Institute of Mechanical and Electrical Engineering, National Taipei University of Technology, Taipei 10608, Taiwan
5Department of Thoracic Surgery, Mackay Memorial Hospital, Taipei 10449, Taiwan
6Department of Civil Engineering, Texas A & M University, College Station, TX 77843-3136, USA

Received 8 March 2013; Accepted 21 May 2013

Academic Editor: Georgios Tzamalis

Copyright © 2013 Ho Chang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study used natural dyes as sensitizers of dye-sensitized solar cells (DSSCs) to replace expensive chemical synthetic dyes. We prepared two natural dyes, chlorophyll dye and anthocyanin dye, by extracting them from wormwood and purple cabbage, respectively. Moreover, we mixed the prepared chlorophyll dye and anthocyanin dye at 5 different volume ratios to form cocktail dyes. For preparation of photoelectrode, P25 TiO2 nanoparticles were used to prepare paste, which was coated on fluorine-doped tin oxide (FTO) conductive glass by the spin coating method at different spin coating speeds in order to form TiO2 thin films with different thicknesses. The DSSC prepared by the cocktail dye achieves photoelectric conversion efficiency (η) of 1.95%, open-circuit voltage ( ) of 0.765 V, and short-circuit current density ( ) of 5.83 mA/cm2. Moreover, the prepared DSSC sensitized solely by chlorophyll extract of wormwood achieved a photoelectric conversion efficiency (η) of 0.9%, whereas the DSSC sensitized solely by anthocyanin extract of purple cabbage achieved a photoelectric conversion efficiency of 1.47%, achieving the longest lifetime of electrons amongst these three dyes.