Department of Chemistry, University of Oregon
Role of Fractal Patterns on New Materials for Solar Energy Applications: Inorganic Clusters, Films and Fractal Geometry Simulation
Two University of Oregon Researchers Receive
Prestigious Scialog® Award for High-Risk Science
Two innovative University of Oregon researchers have teamed up under a $250,000 grant to take a high-risk approach to improving the efficiency of converting sunlight directly into electricity.
Physics Professor Richard Taylor and Darren Johnson, an associate professor of inorganic, organic, supramolecular and materials chemistry, received the grant from Research Corporation for Science Advancement (RCSA). RCSA is America’s second-oldest foundation, established in 1912.
Specifically, Taylor and Johnson were funded to explore the use of fractal geometry – one of Taylor’s major interests. The term fractal was coined by Polish-born mathematician Benoit Mandelbrot in 1975. He took it from the Latin “fractus,” meaning “broken” or “fractured.” Fractal geometry is found everywhere in nature. For example, Taylor said, it is present in plants and trees in the repeating patterns of leaf clusters and in leaf veins.
RCSA made the grant through its Scialog® program. Scialog – from the words “science” and “dialog” -- funds high-risk/potentially high-reward research in the hope that it will lead to “the major scientific breakthroughs the world requires to address pressing global needs,” said RCSA President and CEO James M. Gentile.
Before receiving the grant, Taylor was collaborating with other researchers on a project to use fractal patterns in tiny electronic photoreceptor cells that may eventually be implanted in the eyes of blind people. Johnson, meanwhile, was exploring how to make relatively large quantities (by laboratory standards - a few grams, really) of nanoclustered indium-based compounds.
“Nano” is a suffix meaning “very small” – under 100 nanometers (one nanometer is one billionth of a meter). Researchers worldwide are interested in nanoscale physics and chemistry because, as physicist Richard Feynman famously pointed out in 1960, ordinary matter can behave quite differently on the nanoscale, where quantum mechanical effects are more pronounced.
Solar energy researchers are especially interested in the photoelectric properties of nanoscale materials, including nanomaterials containing the element indium that Johnson has been working with. Because of its electrical properties and its transparency in certain forms, indium has long been used in the electronics industry, chiefly in combination with other elements such as tin. Many big-screen TVs are made with some type of indium compound. However, when combined with other earth-abundant elements such as gallium, copper and/or sulfur or selenium, the resulting nanomaterials can have good properties for solar power generation.
Taylor and Johnson will use their Scialog grant to determine which fractal patterns might best support highly efficient solar devices. At the same time, they will synthesize new inorganic (non-carbon-based) nanoclusters. The plan is to put these nanoclusters into inks, which will allow the researchers to print, perhaps via inkjet printers, relatively inexpensive devices to convert sunlight into electricity. Ultimately, they hope to print in fractal patterns that mimic, or even improve upon, the light-harvesting patterns found in nature.
“Fortunately, we have an extensive network of researchers and organizations at the University of Oregon to help us with this challenging project,” Johnson said.
RCSA’s Scialog program requires awardees – known as Scialog fellows – to meet yearly to trade ideas and insights in an open, no-holds barred series of discussions designed to heighten creativity and generate radically new ideas for scientific research.
“Scialog is an experiment being conducted by RCSA,” Gentile said. “The goal is to see if we can accelerate scientific innovation.”
The discussions on solar energy have been held at Biosphere2, in the desert north of Tucson, Arizona. Taylor and Johnson, who received their Scialog award earlier this year, attended the most recent conference this past October.
The massive glass and steel Biosphere 2 structure – bigger than two football fields - was built between 1987 and 1991 at a cost of more than $2 million. It was designed to study the interaction of humans and plants in the world’s largest sealed environment. Two “missions” involving humans in the Biosphere were ended prematurely, prompting the media and the general public to view the endeavor as a “failed” experiment.
But Gentile said there are really no failed experiments in science, merely experiments that do not confirm their hypothesis. “These so-called failures often yield important information that point us to new and useful insights.”
He said RCSA chose Biosphere2 as its base for the Scialog program for just that reason. “In science it’s important to take risks, and risk-taking, by its very nature, involves the possibility of failure. But we can’t learn new things and develop new paradigms without taking those risks.”
Gentile added that many important insights have come out of Bisophere2, despite its public reputation. “Most people don’t know that our current understanding about the plight of coral reefs in a warming world due to increasing levels of atmospheric carbon dioxide came from Biosphere2, and not from some research lab on the seacoast.”
Biosphere2, home to numerous ongoing environmental and climate-related studies, is currently administered by the University of Arizona College of Science. The National Science Foundation and the University of Arizona co-sponsor the annual Scialog conferences.