Race is on for Energy Efficiency

As the world becomes ever more dependent on energy, worries over disappearing fossil fuels and other standard sources of power are front and center in a growing international debate. Add to that questions about global warming and you have the makings of an intense race for new and renewable energy sources.

UC Santa Barbara’s new Center for Energy Efficient Materials(CEEM) is taking on some of the big questions by using new materials to make more-efficient and lower-cost solar cells, longer-lasting and higher-capacity batteries, more-efficient solid state lighting, and novel thermoelectric devices to convert waste heat to useful electrical energy.

Funded for five years with $19 million from the American Reinvestment and Recovery Act, the new center is one of 46 Energy Frontier Research Centers established by the Department of Energy in 2009. It focuses on material science, which is one of UC Santa Barbara’s great strengths, says David Auston, the new executive director of the center.

“The goal of the center is to lay the foundation for the basic research needed to solve some of the world’s most pressing energy-related problems,” Auston explains. “So we are working on organic and inorganic solar cells, light-emitting diodes, new nano-structured materials, and devices to convert heat to electricity. The center also places a strong emphasis on understanding the materials and how their unique physical and chemical properties might apply to these pressing energy needs.”

CEEM is part of the broader Institute for Energy Efficiency, which engages in a wider range of activities related to energy, for example, building and computing efficiencies.

“Like the Institute, CEEM is cross-disciplinary and highly collaborative. It’s very much a team effort,” Institute Director John Bowers says.

Solar cells made out of new materials hold tremendous promise for reducing energy use worldwide. Currently, most commercially available solar cells are made out of silicon. Researchers have found that incorporating other elements into silicon solar cells increases the efficiency of turning light into electricity. CEEM researchers are using this strategy to develop new high-efficiency solar cells by applying elements known as “group III-nitrides” to silicon cells, which increases the band-gap range (or the range of wavelengths of light that can be converted into electricity). Separately, CEEM researchers have made breakthroughs in the field of organic “plastic” solar cells by synthesizing new materials that demonstrate efficiencies in excess of 15 percent, where previously the best efficiencies were about 5 percent. The most efficient silicon cells are able to capture about 25 percent of light energy. Unlike silicon cells, which are rigid, plastic cells are thin, flexible films that can be applied like paint and literally printed like ink, using “standard printing tools,” thus making them potentially much less-expensive to produce and install.

New thermoelectric materials (materials that convert temperature changes into electricity) are under investigation and will allow for a variety of new applications, for example a compact alternative to internal combustion engines in cars and solid state refrigerators that do not need the environmentally unfriendly gas freon to cool.

In the area of lighting, scientists seek the creation and understanding of new materials that can improve efficiencies of light-emitting diodes (LEDs). LEDs have the potential to revolutionize lighting worldwide. They last more than 20,000 hours before burning out, consume very little power, don’t generate UV radiation, and there is no radiated heat from the light, among other factors.

A major hurdle is cost, but researchers predict they will have LED bulbs that will be competitive with fluorescent and incandescent bulbs within a year or two. LED lighting is still relatively expensive, about $40 per 1,000 lumens, while prices for incandescent bulbs are about $1 per 1,000 lumens. UCSB’s Shuji Nakamura, who was the first to develop a blue LED (the precursor to today’s white LED), says prices need to plunge to $1 to $2 per 1,000 lumens in order for LED to compete in the open market. Thus, the search for less-expensive materials.

Finally, CEEM researchers seek new ways to harness, store and deliver energy. They have already developed a revolutionary new, bio-inspired, low-cost, low-temperature method for the kinetically controlled synthesis of nano-structured metals and semiconductors. These new materials exhibit energy capacity 30 percent greater than present commercial materials.

All of this research is interdisciplinary and engages scientists throughout the UC Santa Barbara campus and at UC Santa Cruz, Harvard University, the National Renewable Energy Lab in Golden, CO, and the Los Alamos National Lab in New Mexico.

“The entire field has significant social impact,” Auston says. “Students get excited and engaged. Energy, saving the planet and preventing global warming are all about getting involved now.”

In addition to conducting basic research, the new center sponsors a series of seminars and provides an opportunity for undergraduates to participate as interns in the research projects. Find out more at the center’s Web site.