Solar Cells Powered by Rain?


Researchers in China say they’ve developed a solar cell that can work in all weather—and that derives electric power from raindrops.

Qunwei Tang, professor of materials science at Ocean University of China, is lead author on the study in the journal Angewandte Chemie. The study, published in March, suggests the use of a film of graphene on the solar cells.

Graphene is a two-dimensional form of carbon; its discoverers won the 2010 Nobel Prize in Physics. According to the scientists, graphene conducts electricity well and is rich in delocalized electrons.

When raindrops interact with the graphene, the result is “double-layer pseudocapacitors,” the researchers write. This produces a measurable amount of voltage and current.

The Secret is the Salts

The key isn’t in the water itself, but in the salts that raindrops contain, according to the study authors. Positively charged ions from the salts in the rainwater bind with electrons in the graphene.

In practical terms, the idea of a cell powered by both sun and rain could be an important development. The researchers note that “all-weather solar cells are promising in solving the energy crisis,” addressing a major downfall of solar cells as a power source—the weather.

A Work in Progress

The cells created for the study may not be ready for prime time, though. The authors say the optimal conversion efficiency for the solar component is 6.53 percent, and they measure the energy produced by raindrops on the graphene film in terms of hundreds of microvolts.

They say that “the new concept can guide the design of advanced all-weather solar cells.”

Since its development, graphene has been touted as a super strong (though perhaps not always super-tough) material with innumerable potential uses. It’s been eyed for use as a conductor, a protective coating and even a filter for salt water.

Tang worked with Xiaopeng Wang and Dr. Benlin He, both of Ocean University, and Prof. Peizhi Yang, of Yunnan Normal University, on the research.


Tagged categories: Asia Pacific; Coating chemistry; Coatings Technology; EMEA (Europe, Middle East and Africa); Energy efficiency; Graphene; Latin America; North America; Research; Solar energy

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