Efficiency enhancement of organic photovoltaics by addition of carbon nanotubes into both active and hole transport layer

We investigate the effect of the incorporation of single walled carbon nanotubes (SWNTs) into both the active layer and the hole transport layer (HTL) on bulk heterojunction organic photovoltaic devices. The overall efficiency gain for such a device is 40%, compared with the pristine device. The observed efficiency gain is attributed to a more efficient exciton dissociation due to the SWNTs presence in the photoactive layer and an overall enhanced hole transport and collection through the SWNTs percolation paths, which are extended in both the active layer and the HTL. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3690056]