Graphene oxide doped single-walled carbon nanotube thin film as back electrode for CdTe solar cell

We prepared single wall carbon nanotubes (SWNTs) thin films and Graphene oxide doped SWNT (GO-doped SWNT) composite thin films via vacuum filtration and transferring techniques. The SWNT and GO-doped SWNT films along with gold (Au) were applied as back electrode for Cadmium telluride (CdTe) solar cells, in place of the traditional copper/gold (Cu/Au) back electrode. Our results show that the CdTe cells with GO-doped SWNT films have significant higher average open circuit voltage (Voc ~0.6V) than the devices with SWNT films alone (Voc 0.4~0.5V) under AM1.5 illumination. The enhancement is mainly ascribed to the doping effect of GO which modifies the work function of SWNT and reduces the hole transporting barriers at the CdTe/SWNT interface.