Functionalized carbon nanotubes in donor/acceptor-type photovoltaic devices

We have introduced functionalized multiwalled carbon nanotubes (CNTs) in donor/acceptor-type photovoltaic devices. We fabricated the devices based on heterostructure between polymer-CNT composite and buckminsterfullerene (C-60) layers. Due to the functional groups of the CNTs, a homogeneous blend of CNT-polymer composite could be obtained. In the composite, the nanotubes acted as exciton dissociation sites and also hopping centers for hole transport. The CNTs in the polymer-CNT/C-60 device provided higher exciton dissociation volume and increased mobility for carrier transport. We have observed an increase in open-circuit voltage and short-circuit current in the polymer-CNT/C-60 devices as compared to the polymer/C-60 ones.