Fabrication of double-walled carbon nanotube counter electrodes for dye-sensitized solar sells

Double-walled carbon nanotubes (DWCNTs) have been studied for counter-electrode application in dye-sensitized solar cells (DSCs). Mesoporous TiO2 films are prepared from the commercial TiO2 nanopowders by screen-printing technique on optically transparent-conducting glasses. A metal-free organic dye (indoline dye D102) is used as a sensitizer. DWCNTs are applied to substitute for platinum as counter-electrode materials. Morphological and electrochemical properties of the formed counter electrodes are investigated by scanning electronic microscopy and electrochemical impedance spectroscopy, respectively. The electronic and ionic processes in platinum and DWCNT-based DSCs are analyzed and discussed. The catalytic activity and DSC performance of DWCNTs and Pt are compared. A conversion efficiency of 6.07% has been obtained for DWCNT counter-electrode DSCs. This efficiency is comparable to that of platinum counter-electrode-based devices.