Simulation of resonance energy transfer in carbon nanotube composites for photovoltaic applications

Carbon nanotubes (CNTs) are interesting for use as the light-absorbing material in photovoltaic devices. We study the intertube exciton transfer rates in CNT films. The excitonic states in semiconducting CNTs are calculated by solving the Bethe-Salpeter equation. The resonance energy transfer rates are calculated using Fermi´s golden rule. We calculate the exciton transfer rate between two CNTs as a function of their relative angle and also the effect of exciton confinement on the energy transfer rate. Our results show that the exciton confinement decreases the transfer rate between CNTs with similar chiralities. However, the transfer rate between CNTs with dissimilar chiralities increases as a result of exciton confinement.