Lightweight solar cells track the sun, providing 40 percent more energy than fixed cells

Engineers have developed an array of solar cells that can capture 40 percent more energy than fixed solar cells. By borrowing from kirigami (the Japanese art of paper cutting), the cells are aimed at different angles, allowing for part of the array to be always perpendicular to the Sun’s rays.
“The design takes what a large tracking solar panel does and condenses it into something that is essentially flat,” said Aaron Lamoureux, a doctoral student in materials science and engineering and first author on the open-access paper in Nature Communications. Residential rooftops would need significant reinforcing to support the weight of conventional costly sun-tracking systems, he said.
To explore patterns for the array, the engineers worked with paper artist Matthew Shlian, a lecturer in the U-M School of Art and Design, who showed them how to create the solar array in paper using a plotter cutter. Lamoureux then made more precise patterns in Kapton, a space-grade plastic, using a carbon-dioxide laser.
Although the team tried more complex designs, the simplest pattern worked best. With cuts like rows of dashes, the plastic pulled apart into a basic mesh. The interconnected strips of Kapton tilt at different angles in proportion to how much the mesh is stretched, to an accuracy of about one degree.
The design with the very best solar-tracking promise was impossible to make at U-M because the solar cells would be very long and narrow. Scaling up to a feasible width, the cells became too long to fit into the chambers used to make the prototypes on campus, so the team is looking into other options.
“We think it has significant potential, and we’re actively pursuing realistic applications,” said Max Shtein, associate professor of materials science and engineering. “It could ultimately reduce the cost of solar electricity.”
The study was funded by National Science Foundation and NanoFlex Power Corporation. The university is pursuing patent protection for the intellectual property, and is seeking commercialization partners to help bring the technology to market.