Putting a New Spin on Electronics
by Jeffrey Martin '04, '05 (M.A.)
The modern world works because of ones and zeroes. Information speeds across countries and oceans using the computer language of binary arithmetic. But what would it mean for the future of electronics if we could change how these bits of information are moved from one place to another?
“On a basic level, electronics measure the charge of electrons passing through circuits typified by a voltage,” explains Paul Angiolillo, Ph.D. ‘78, associate professor of physics. “The ones and zeroes in current electronic systems indicate whether a voltage pulse is present (a one) or absent (a zero). That is how information is stored and transferred.”
For the past two decades, Angiolillo has been studying how electrons travel in novel organic semiconductors. In recent papers published in The Journal of Physical Chemistry, Chemical Communications, and The Proceedings of the National Academy of the Sciences, he has focused his research on not only charge dynamics, but on another of the electron’s quantum properties: its spin.
Electron spin can be observed because it generates a small magnetic field, that under special conditions, is oriented either up (a one) or down (a zero). That magnetic field can carry information in a manner similar to the charge binary system. Research on the concept has been conducted in part by Isabella Goodenough ’16, a chemistry major and McNulty Fellow, who has worked in Angiolillo’s lab for the past two years. Her work has shown that electron spin states live for relatively long times, making them amenable to being manipulated for information transfer.
Angiolillo’s research, which is done in collaboration with chemists at Duke University, will also shape the future of how we harvest energy from the sun, a practice known as photovoltaics. Current solar technology employs silicon-based materials, which is costly. In a recently-accepted manuscript in the journal The Proceedings of the National Academy of the Sciences, Angiolillo and his coworkers demonstrated unprecedented electron mobility in an organic material, a prerequisite for photovoltaic devices.
“Using organic materials means that we can develop smaller, thinner, more flexible collection devices,” Angiolillo explains. Gone would be the days of expansive, rigid solar arrays in the middle of the desert. “We could sandwich a transparent sheet between two panes of glass,” he imagines. “Or wrap a car with it. Or include it in a jacket.”
While Angiolillo acknowledges that widespread production and use of this type of material could be “a couple generations away,” he stresses the importance of the research.
“Energy and climate-related issues trump every other issue in the world right now,” he says. “Physicists can play a major role in developing new technologies that will revolutionize these fields. That’s why our work — and the continuing education of physics students — is so crucial.”