Biomimicry Could Lead To Solar Cells That Store Energy For Several Weeks

Jeez, look at this! The main problem with solar is that you couldn't store the energy. So as much as you could get from the sun, you had to use up pretty quickly or it would be so much wasted energy. So the thing people have been cracking their heads over is how to store this energy so it could be used for future purposes. So read this article, which appeared in Forbes, and was filtered and sent to me by The Intelligent Optimist.

And rejoice!

The lack of low cost, large scale energy storage systems is a big problem for solar power. Today, the typical solar cell can only store energy for only a few microseconds. As a result, customers equipped with solar panels will for the foreseeable future remain dependent on the electric power grid.

This is why so many green energy gurus consider hybrid systems combining solar and storage to be the mother of all disruptive technologies.

A new study by chemists at the University of California, Los Angeles (UCLA) suggests that rather than combining solar and storage, it may be easier to design solar cells that can do double duty as batteries.

The study, which was published in the most recent issue of the journal Science, describes a process for designing solar cells is capable of storing electricity for as long as several weeks at a time.

The solar cells, which are made from plastic rather than silicon, mimic a mechanism used by plants to generate energy through photosynthesis.

“Biology does a very good job of creating energy from sunlight,” said Sarah Tolbert, a UCLA professor of chemistry and one of the senior authors of the research. “Plants do this through photosynthesis with extremely high efficiency.”

The new technology has two basic elements: a polymer donor and a nanoscale fullerene acceptor. The polymer donor absorbs sunlight and passes electrons to the fullerene acceptor, which generates electricity.

Here is a great analogy used by UCLA’s press release to explain how the system works:

The plastic materials, called organic photovoltaics, are typically organized like a plate of cooked pasta — a disorganized mass of long, skinny polymer ‘spaghetti’ with random fullerene ‘meatballs.’ But this arrangement makes it difficult to get current out of the cell because the electrons sometimes hop back to the polymer spaghetti and are lost. . . . The UCLA technology arranges the elements like small bundles of uncooked spaghetti with precisely placed meatballs. Some fullerene meatballs are designed to sit inside the spaghetti bundles, but others are forced to stay on the outside. The fullerenes inside the structure take electrons from the polymers and toss them to the outside fullerene, which can effectively keep the electrons away from the polymer for weeks. In the new system, the materials self-assemble just by being placed in close proximity.

“In photosynthesis, plants that are exposed to sunlight use carefully organized nanoscale structures within their cells to rapidly separate charges — pulling electrons away from the positively charged molecule that is left behind, and keeping positive and negative charges separated,” said Tolbert. “That separation is the key to making the process so efficient.”