Front and Back-Junction Carbon Nanotube-Silicon Solar Cells with an Industrial Architecture

In the past, the application of carbon nanotube-silicon solar cell technology to industry has been limited by the use of a metallic frame to define an active area in the middle of a silicon wafer. Here, industry standard device geometries are fabricated with a front and back-junction design which allow for the entire wafer to be used as the active area. These are enabled by the use of an intermixed Nafion layer which simultaneously acts as a passivation, antireflective, and physical blocking layer as well as a nanotube dopant. This leads to the formation of a hybrid nanotube/Nafion passivated charge selective contact, and solar cells with active areas of 1-16 cm(2) are fabricated. Record maximum power conversion efficiencies of 15.2% and 18.9% are reported for front and back-junction devices for 1 and 3 cm(2) active areas, respectively. By placing the nanotube film on the rear of the device in a back-junction architecture, many of the design-related challenges for carbon nanotube silicon solar cells are addressed and their future applications to industrialized processes are discussed.