Synthesis of MWNTs using thermal chemical vapor deposition for the application of a counter electrode for DSSCs

MWNTs (Multi-wall Carbon nanotubes) were grown using thermal CVD at a low temperature of 530 °C to be fabricated as a counter electrode of dye-sensitized solar cells (DSSCs). Ammonia gas and acetylene gas were introduced as reactive gas sources with 90 sccm and 108 sccm, respectively. DSSCs using CNT and Pt counter electrodes were fabricated using conventional method to compare its efficiencies. As a result, comparable electrical and optical properties were obtained for both electrodes. UV transmittance for the fabricated CNTs was higher than that for Pt electrode. Moreover, the cell efficiency of each DSSC was measured to be 0.99% and 0.85% using CNT and Pt counter electrodes, respectively. Therefore, the cell efficiency using the CNT counter electrode was comparable to that using the Pt counter electrode. Overall, it was found that directly grown MWNTs at low temperature are a highly promising material to be used as a counter electrode for DSSC.