Demonstration of Point Contact Geometry for Solar Cells Using Single Walled Carbon Nanotube

Fadhil K. Alfadhili, Adam B. Phillips, Manoj K. Jamarkattel, Bhuiyan M. Anwar, Prabodika N. Kaluarachchi, Zahrah S. Almutawah, Abdul Quader, Deng-Bing Li, Yanfa Yan, Randy J. Ellingson, Michael J. Heben Wright Center for Photovoltaics Innovation and Commercialization, Department of Physics and Astronomy, University of Toledo, Toledo, OH, United States

Passivation of back interfaces of CdTe-based devices will be critical to achieve the highest efficiency device performance. While AlOx has been shown to passivate the interface of CdTe films, it can also lead to a blocking layer when used as a back contact. Here we provide a pathway for hole transport through the passivating AlOX by incorporating single walled carbon nanotubes (SWCNTs) to form a point contact geometry. By varying the concentration of the AlOx precursor, SWCNTs, and surfactant, we are able to change the shape of the current density-voltage curve from having a strong s-kink behavior, indicative of blocking behavior, with low SWCNT ratios to no s-kink behavior with high SWCNT, low surfactant concentrations. We use back illuminated device measurements to show that both the AlOx and SWCNTs are necessary to achieve the best current collection.