University of Connecticut (UConn) researchers have developed a light-harvesting antenna that they say could double the efficiency of existing solar cell panels and make them less expensive to build.

Sunlight strikes Earth every day with more energy than is used globally in a year. However, finding an efficient way to capture and store solar energy to replace fossil fuels as the world’s go-to energy source remains a challenge.

Challa V. Kumar, UConn professor of biological and physical chemistry, and his team from the Institute of Materials Science have created a gel that enhances the ability of solar cells to absorb energy from sunlight.

Gel that enhances solar cells' absorption of energy from sunlight could double the efficiency of solar cell panels. Image credit: Peter Morenus/UConn Photo.Taking inspiration from plants, the team used a mixture of biodegradable materials to collect sunlight, much like plant chlorophyll. The concoction includes cow blood protein (a waste product in the meat industry), fatty acid from coconuts and organic dyes.

Together these substances form a gel that, when placed in a type of solar cell known as a Gratzel cell, increases the absorption of unused photons and the cell’s power output. According to Kumar, this process is useful for coating solar cells’ light-emitting diodes, which mostly emit in the blue region of the spectrum.

“Most of the light from the sun is emitted over a very broad window of wavelengths,” he says. Kumar recently presented his work at the 250th National Meeting & Exposition of the American Chemical Society in Boston. “If you want to use solar energy to produce electric current, you want to harvest as much of that spectrum as possible.”

Silicon photovoltaic solar cells, the most common type currently used on rooftop panels to convert photons—tiny particles of light—into electricity, cannot take advantage of the blue part of the light spectrum. Only photons with the right amount of energy can be absorbed by the photovoltaic cell.

The antenna built by Kumar and his team collects unused blue photons in the light spectrum and, via a process of “artificial photosynthesis,” converts them to lower energy photons that the silicon can turn into current.

He says the gel is easy to make and relatively inexpensive, but the mixture needs to be stable and durable enough to last many years in order to be usefully incorporated into existing manufacturing techniques.

Ultimately, he hopes to integrate the technology into the manufacturing process of solar panels to make them more affordable and efficient.

UConn has filed a provisional patent application, and Kumar is working with a Connecticut company on how to apply the gel to silicon solar cells.

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