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Scientists at DuPont and Cornell University 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. 

Scientists at the National Institute of Advanced Industrial Science and Technology (AIST) in Japan have developed a new technique for the mass production of unique metal-complex-type organic nanotubes. It was found that the nanotubes can be obtained when an aqueous metal salt solution is added to an alcoholic suspension of amphiphilic molecules comprising glycylglycine and fatty acids. In this process, the sheet-like structure of the amphiphilic molecules was found to change to a nanotube structure within 10 minutes. This method of synthesis has been extended to the mass production of organic nanotubes. The new technique is almost five times faster than the conventional method, and the amount obtained is 200 times that obtained in the conventional method. Learn more details Here.

Professor Yang Yang from UCLA has led a team of researchers at the university’s Henry Samueli School of Engineering and Applied Science in creation of a new polymer for solar cells that increases the sunlight absorption and conversion capabilities that previous polymers could not achieve.
In the 26 November issue of the Journal of the American Chemical Society, Yang and his team described how by substituting a silicon atom for a carbon atom in the backbone of the polymer, they were able to enhance the material’s PV properties. They noted that the silole-containing polymer could also be crystalline, which gives it even more potential for high-efficiency solar cells. Learn more details Here.

Japan's National Institute of Advanced Industrial Science and Technology (AIST) achieved 7.6% cell conversion efficiency with a dye-sensitized solar cell that uses an ionic liquid electrolyte.
The conversion efficiency is the world's highest level for solar cells of that kind, according to the institute. Compared with the existing dye-sensitized solar cells that use a ruthenium (Ru) complex, the new solar cell features an improved durability and a lower material cost.
The solar cell was fabricated by using a newly-developed organic dye called "MK-2" for the light absorbing material. In the past, the institute used a coumarin dye in an organic solvent electrolyte and achieved a conversion efficiency of 8%.
However, it involved problems including a short electron lifetime and a low electron mobility from the dye to the titanium oxide electrodes. To solve these problems, AIST synthesized the MK-2 dye with a molecular design technology.  For more information Here.

Researchers at the University of South Florida have developed solar cells that are one-fourth the size of a grain of rice. When 20 of them are grouped together in an array, they can generate about 7.8 volts of electricity.
While 7.8 volts doesn't sound like much, the potential applications for these tiny cells are pretty cool. The cells are made of an organic polymer that can be dissolved or applied to flexible materials instead of the usual brittle silicon wafers. This flexibility plus their small size would allow them to be sprayed or painted onto surfaces like houses, cars, clothing or anything that is exposed to sunlight.
Head researcher Xiaomei Jiang is working towards one use in particular for these tiny arrays: powering microscopic chemical sensors for soldiers in the field. Batteries are heavy for soldiers to carry and they also cost the military about $57,000 per soldier per year. Having a small, renewable source of power for these types of devices would be in the military and the soldiers' interests.
Jiang is currently working to double the electricity output of these cells, hopefully enough to power the chemical sensors. He believes this is possible within months.

Some of the tiniest solar cells ever built have been successfully tested as a power source for even tinier microscopic machines. An article in the inaugural issue of the Journal of Renewable and Sustainable Energy (JRSE), published by the American Institute of Physics (AIP), describes an inch-long array of 20 of these cells -- each one about a quarter the size of a lowercase "o" in a standard 12-point font. The cells were made of an organic polymer and were joined together in an experiment aimed at proving their ability to power tiny devices that can be used to detect chemical leaks and for other applications, says Xiaomei Jiang, who led the research at the University of South Florida. For more details Here.