Carbon Single Wall Nanotubes As a Low-Barrier, Copper-Free Back Contact to CdTe Solar Cells
Here, we discuss results1 that demonstrate that carbon single-wall nanotube (SWNTs) films can make a high-performance electrical back contact to CdTe solar cells without the use of Cu. Back contacts formed with SWNT films showed improved open circuit voltage in comparison to cells fabricated with standard Au/Cu back contacts and, once overcoated with a thin metal layer, the solar-to-electric conversion efficiency was higher as well. The results are understood by considering that individual SWNTs within the film extend through the film’s thickness and make barrier-less contacts to individual CdTe grains in the active layer of the device.
This work was supported by the U.S. Department of Energy under Award Number DE-SC0006349 and by faculty start-up funds from the University of Toledo, and was conducted in collaboration with the Wright Center for Photovoltaics Innovations and Commercialization (http://www.utoledo.edu/research/pvic/)
(1) Phillips, et al., Nano Lett., 2013, 13 (11), pp 5224–5232