Improved energy conversion efficiency of CdS quantum dots sensitised solar cells using TiO2/carbon nanotube nanocomposite photoanodes

CdS quantum dots sensitised solar cells were fabricated based on TiO2/carbon nanotube nanocomposite photoanodes obtained by a sol-gel process. An energy conversion efficiency increment of about three times is achieved for the solar cell with carbon nanotube content of 0.36 wt-%, and it was disclosed that the enhanced energy conversion efficiency mainly depends on the carbon nanotube content in nanocomposite photoanodes. With the carbon nanotube content increasing from 0.00 to 0.36 wt-%, the energy conversion efficiency of solar cell significantly improved from 0.38 to 1.15% because of the enhanced photogenerated electron collection efficiency and increased adsorption amount of CdS quantum dots. When the carbon nanotube content is up to 0.48 wt-%, however, the energy conversion efficiency declines to 0.75% because of a decrease of photogenerated electron collection efficiency and sensitiser adsorption.