How Does a Solar PV Cell Create Flowing Electricity?

The world we live in today runs on electricity. Electricity is the flow of negative charge. It is everywhere- it is in our cars, our workplace, even in our homes. We use it for lighting for entertainment, and even to keep our food cold. But where does this electricity come from?

Well, most of the electricity that runs our lives comes from burning fossil fuels like gasoline and coal. While fossil fuels are cheap, our environment pays a huge cost. Gas is produced from burning fossil fuels and can introduce toxic fumes, which can cause health problems and contribute to global climate change.

But where else can we get this electricity from?

Solar energy provides an alternative to producing electricity that is clean and renewable with no cost to the environment. A solar panel on our roofs can turn sunlight into electricity.

But how do these solar panels work

It all starts with the Sun. The Sun provides us with light in the form of photons- like Frank. Let's follow Frank the Photon along his journey to become electricity.

First Frank must make the long journey from the Sun to the Earth and then find his way into a solar panel. When Frank enters the solar panel, he finds himself surrounded by many molecules. Eventually Frank interacts with one of these molecules. This interaction is called absorption. When Frank the photon is absorbed he gives his energy to Eddie the Exciton. This energy wakes Eddie up. Because Eddie is so energetic, he decides to go for a little walk. While walking, Eddie runs into a region with new molecules. This region where his molecules and the new ones intersect is called an interface. At the interface, half of Eddy feels like he belongs on the other side of the interface with the new molecules, but the other half of Eddie wants to stay. Eddie then splits up into two parts Ed and Dee. Ed is a negative charge, and Dee is a positive charge. Ed and Dee wave goodbye to one another and wander apart. Now that Ed is negative and all alone, he feels compelled to leave the solar panel. So this is how energy from the Sun, like Frank the Photon, can get turned into electricity with millions of charges like Ed flowing into your home.

So why don't we see solar panels on the roof of every house?

Well, compared to fossil fuels, these solar panels cost a lot more because the technology is not fully developed. However, at the Massachusetts Institute of Technology, scientists are working hard to get more electricity out of each solar panel. Sometimes, electricity gets lost when Frank the photon is absorbed. If Frank doesn't give all of his energy to Eddie the Exciton, and that energy goes to waste. Scientists have found that some molecules are able to take advantage of this extra energy from Frank, to make to excitons just like Eddie. This can give us more electricity. Another way solar panels can lose electricity is when a positive and negative charge find each other and cancel each other out. Researchers are working on a way to prevent this from happening. Through these types of breakthroughs and solar panel technology, we can dramatically decrease our dependence on fossil fuels to keep the environment clean and ensure energy resources for a brighter tomorrow.