Record Efficiency of Air-Stable Multi-Walled Carbon Nanotube/Silicon Solar Cells

Multi-walled carbon nanotube (MWCNT) lms form ecient heterojunction solar cells with n-type crystalline silicon (n-Si), due to their superior optical and electrical properties. Here, we report air-stable photovoltaic devices with record photoconversion eciency of 10%. We realized thin lms consisting of MWCNTs arranged in semitransparent random networks deposited on n-Si substrates by a simple, rapid, reproducible, and inexpensive vacuum ltration process at room temperature. Such heterojunctions favor high and broadband carrier photogeneration, extending the Si spectral response from near infrared to near ultraviolet range; charge dissociation of ultrafast hot carriers [1]; transport of electrons through n-Si and high-mobility [2] holes through the MWCNT percolative network. Furthermore, by varying the MWCNT lm thickness, it is possible tailoring its optical and electrical properties, therefore the overall device optoelectronic features. These results not only pave the way for low-cost, ecient, and broadband photovoltaics, but also are promising for the development of MWCNT-based optoelectronic applications.