Graphene and carbon nanotube based PV electrodes
Both graphene and carbon nanotubes have very high electrical conductivities and mechanical strength, which makes them ideally suited for use as electrodes for flexible solar cells, replacing costly and brittle ITO and FTO. Over the past years, graphene monolayer electrodes, graphene flakes and carbon nanotubes as both electron and hole collecting layers in PV cells have been investigated successfully. The versatility of this approach has been demonstrated by making PV cells using perovskite, organic semiconductor and colloidal quantum dot absorbing layers. For example, it was shown that it is possible to reach more than 18% efficiency with carbon nanotube top electrodes in perovskite solar cells. Furthermore, it has been found that non-conducting polymers wrap carbon nanotubes and can produce very high quality electronic films.
Building on these results this project will continue with the development of nanotube/ polymer/graphene/titania/tin oxide combinations to produce the next generation of nanohybrid particles. It will aim at exploring the possibilities of using non-conjugated polymers to wrap carbon nanotubes for making conductive films and how to integrate graphene and carbon nanotube based electrodes into PV cells both as external contacting layers and as internal electrodes capable of implementing tandem cell designs for various PV technologies. In addition to spin-coating, we will explore the capabilities of a custom made spray-coater in the department which can deposit nanoparticles including carbon nanotubes, aiming to make this process compatible with roll-to-roll fabrication.