Solar power is one of the best ways to make electricity. It’s clean and doesn’t consume any non-renewable resources, like oil and coal. It takes energy from sunlight and converts it to electricity. The challenge is that solar power could be more efficient. Only a few of the photons (those little packets of light) that strike a solar panel are eventually converted into electrical current. If more could be captured and converted, then smaller solar panels (like the one shown on the right) could be used to generate the electricity instead, of the large ones that are used today.

The current types of solar cells produce only one exciton for each photon that strikes it. What’s an exciton? It is a negatively charged electron and a positively charged hole that are bound to each other.

Scientists at the National Renewable Energy Lab in Golden, Colorado and others have shown that quantum dots, tiny nanoparticles can be more efficient for solar energy conversion.

Quantum dots, shown left, are sometimes called artificial atoms, made of chemicals like cadmium and selenium, these tiny particles are only a few nanometers in size. They are so small that they contain only a thousand or so atoms. Together they form a semiconductor, the same stuff used to make computer chips. They are so small that they don’t have any space to store energy.

They can produce three excitons for every photon, meaning that they should produce three times as much electricity as the materials currently used for solar cells. That would help a lot in making new sources of safe energy.

For more information listen to Earth and Sky.

Image Source: Environment News Service | Science News Online