Device Based on Soccer Ball-Shaped Molecules Emits White Light for the First Time
Conventional scientific wisdom says so-called "buckyballs," sixty carbon atoms bound together in the form of a soccer ball, are extremely efficient at quenching light. Now, however, University of California researchers say they have observed the opposite: "the first known example" of white light being given off from a device made of a buckyball derivative.
The development is detailed in a communication to Journal of the American Chemical Society. The peer-reviewed journal is published by the American Chemical Society (ACS), the world's largest scientific society. Text became available on the ACS web May 29 and will appear in the journal's June 16 print edition.
It is relatively easy to produce small molecule or polymeric organic materials that emit orange, yellow, and green light. Deep blue and white light are possible, but a bit more difficult. In fact, several companies are developing organic light emitting devices that they hope to use in products ranging from cell phone displays to automobile bumpers. Until now, however, the use of light-killing buckyballs for such applications seemed unthinkable.
The UC scientists added attachments to buckyballs that modify their electronic structure and allow them to emit light. UCLA chemist and co-author Fred Wudl, Ph.D., currently regards their new device as "an academic curiosity, because normally buckyballs quench luminescence very effectively and here it actually gives off light." Practically speaking, its efficiency is extremely low (only a fraction of a percent of electric power supplied is converted to light) and buckyballs are currently relatively expensive.
The UCLA chemist who first made the buckyball device, co-author Yves Rubin, Ph.D., still allows himself to dream: "Such white light devices might ultimately be used to illuminate rooms by covering a ceiling or wall with the material." At the moment, however, it seems that the companies working on simpler organic materials have a big head start on such applications, according to Wudl.
Other co-authors on the paper are Kate Hutchison, Ph.D. and June Gao, Ph.D. of UC, Santa Barbara and Georg Schick, Ph.D., of UCLA.
A nonprofit organization with a membership of nearly 159,000 chemists and chemical engineers as its members, the American Chemical Society publishes scientific journals and databases, convenes major research conferences, and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio. (http://www.acs.org)
Journal
Journal of the American Chemical Society