Dye-sensitized solar cells made with TiO2-coated multi-wall carbon nanotubes and natural dyes extracted from ipomoea

Abstract

This paper reports the fabrication of photoelectrode of dye-sensitized solar cells (DSSCs) using TiO2-modified multi-wall carbon nanotubes (MWCNTs). The self-developed nanofluid synthesis system is employed to make TiO2 nanofluid which has good roundness and uniform size, at an average particle size of 40nm. The self-prepared TiO2 nanoparticles, after being mixed with TiO2-nanoparticle-modified MWCNTs (TiO 2-CNT) by sol-gel method, are deposited in an indium tin oxide (ITO) conductive glass by electrophoretic deposition method, thus forming a thin film of TiO2/CNTs of 14 μm thick. As seen from the FE-SEM image and Raman spectra, the CNTs adhere well to the TiO2 nanoparticles. In addition, the developed DSSCs make use of the natural dye extracted from ipomoea. The TiO2-nanoparticle-modified MWCNTs prepared by sol-gel method can improve the performance of DSSCs by increasing the short-circuit current density (Jsc). The enhancement of Jsc is attributed to the increased adsorption area of thin films and the improved interconnectivity among TiO2 particles and TiO2-CNTs. Experimental results show that TiO2-modified MWCNTs prepared using natural dye extracted from ipomoea could enhance the light-to-electricity efficiency of DSSCs by as high as 30% (0.278% to 0.359%). © 2009 The Japan Institute of Metals.