Researchers at DuPont, Cornell reveal process to make solely semiconducting carbon nanotube ink

12-Jan-09

Scientists at DuPont and Cornell University in Ithaca, N.Y., have used a simple chemical process to convert mixtures of metallic and semiconducting carbon nanotubes into solely semiconducting carbon nanotubes with electrical characteristics well-suited for plastic electronics. As published in Jan 9 issue of journal Science, research team comprising of DuPont research fellow Dr. Graciela Blanchet, Cornell University associate professor of materials science and engineering George Malliaras, Cornell/DuPont post-doctoral fellow Mandakini Kanungo and DuPont research chemist Helen Luthe have revealed a commercially viable path for the production of bulk quantities of organic semiconducting ink, which can be printed into thin, flexible electronics such as transistors and photovoltaic materials for solar cell technology. The research team has developed a simple chemical process that brought fluorine-based molecules into contact with the nanotubes. Through a process called cycloaddition, the fluorine molecules efficiently attacked or converted the metallic nanotubes, leaving the semiconducting tubes alone, and creating a perfect batch of solely semiconducting nanotubes. The resulting carbon nanotubes were dispersed into semiconducting ink and used in thin film transistors that are designed to be thinner, lighter and use less energy. "A significant limitation in electronic application of carbon nanotubes has been the difficulty in separating metallic from semiconducting carbon nanotubes," Graciela said. The research work revealed economical route to suppress the conductivity of the metallic tubes without requiring further separation of nanotubes by type.