Awards Database

Scialog: Solar Energy Conversion - 2013

Rene Lopez

University of North Carolina at Chapel Hill

20% Efficiency Nanostructured PbS Solar Cells

Rene Lopez, associate professor of physics at the University of North Carolina at Chapel Hill, is exploring methods to more cost-effectively convert sunlight directly into electricity. “We need-low cost and high-efficiency photovoltaic materials to really hope for a solar revolution,” Lopez says. “Sustainable energy research cannot remain blind to this reality.” His research involves attempting to create a new type of photovoltaic device composed of colloidal quantum dots. A quantum dot is a tiny speck of material – in this case the dots will be made of an inexpensive molecule composed of lead and sulfur. Lopez, who is working with a $100,000 Scialog grant from RCSA , is hoping his research will push the lead-sulfur dots to 20 percent efficiency in converting sunlight to electricity. Currently, high-efficiency photovoltaic devices are usually made of more expensive crystalline silicon. Lopez will use a low-cost process called “nanopatterning” to array the dots in a gel-like substance for maximum efficiency. He will also employ an advanced computer program to determine the quantum dots’ ability to absorb photons, the basic particles of light, and the dots’ subsequent ability to transport electrons. The electrons are produced by the dots when photons knock electrons out of their “orbits” around the atoms composing the lead-sulfur molecules. When electrons are collected in this way, they form an electrical current. “This project will use naturally abundant materials to bring quantum-dot photovoltaic devices to energy-conversion efficiencies where they can have an immediate impact on society,” Lopez said.

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