After Gutenberg

Also, back in May ’08, this blog reported upon conductive polymers. We now learn, via Slashdot, where geeks go for their Fullerene needs, that scientists at the US Department of Energy’s Brookhaven National Laboratory and Los Alamos National Laboratory have fabricated transparent, conductive thin films.

Somenath Mitra, PhD, professor of Chemistry and Environmental Sciences at New Jersey Institute of Technology (NJIT) leads one research team developing a fullerene–single wall carbon nanotube complex for polymer bulk hetero-junction photovoltaic cells. More recently, material scientists at Ohio State University report development of a new electrically-conductive plastic. “It operates upon the same principles as standard photovoltaic materials, wherein light energizes the atoms of the material and knocks electrons free to generate a current. Whereas in traditional photo-voltaics the electrons are removed for a fraction of a second, in the new hybrid material the electrons are excited for much longer (7 million times) than before.”

Capable of absorbing light and generating electric charge over a relatively large area, the material could be used to develop transparent solar panels or even windows that absorb solar energy to generate electricity. The material consists of a semi-conducting polymer doped with carbon-rich fullerenes.”

Photo Credit: Loo Research Group

“Princeton researchers have developed a new way to manufacture electronic devices made of plastic, employing a process that allows the materials to be formed into useful shapes while maintaining their ability to conduct electricity. In the plastic transistor pictured here, the plastic is molded into interdigitated electrodes (orange) allowing current flow to and from the active channel (green).

Princeton University engineers also have developed a new technique for producing electricity-conducting plastics. They anticipate that adoption of this thin film process could lower the cost of manufacturing solar panels dramatically.

By overcoming technical hurdles to producing plastics that are translucent, malleable and able to conduct electricity, the researchers have opened the door to broader use of the materials in a wide range of electrical devices.

With mounting concerns about global warming and energy demand, plastics could represent a low-cost alternative to indium tin oxide (ITO), an expensive conducting material currently used in solar panels, according to the researchers.

“Conductive polymers [plastics] have been around for a long time, but processing them to make something useful degraded their ability to conduct electricity,” said Yueh-Lin Loo, an associate professor of chemical engineering, who led the Princeton team. “We have figured out how to avoid this trade-off. We can shape the plastics into a useful form while maintaining high conductivity.”

A multi-institutional team reported on its new technique in a paper published online March 8 in the Proceedings of the National Academy of Sciences.

The area of research, known as “organic electronics” because plastics are carbon-based like living creatures, holds promise for producing new types of electronic devices and new ways of manufacturing existing technologies, but has been hampered by the mysterious loss of conductivity associated with moldable plastics.

“People didn’t understand what was happening,” said Loo, who co-wrote the paper. “We discovered that in making the polymers moldable, their structures are trapped in a rigid form, which prevented electrical current from traveling through them.”

Once they understood the underlying problem, Loo and her colleagues developed a way to relax the structure of the plastics by treating them with an acid after they were processed into the desired form.

Using the method, they were able to make a plastic transistor, a fundamental component of electronics that is used to amplify and switch electronic signals. They produced the electrodes of the transistor by printing the plastic onto a surface, a fast and cheap method similar to the way an ink-jet printer produces a pattern on a piece of paper.