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

Passivation of back interfaces of CdTe-based devices will be critical to achieve the highest efficiency device performance. While AIOx 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 AIOX by incorporating single walled carbon nanotubes (SWCNTs) to form a point contact geometry. By varying the concentration of the AIOx 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 AIOx and SWCNTs are necessary to achieve the best current collection.