The concept of the solar cell is one fairly easy to grasp just by reading the name: it’s a device that takes in and stores energy transmitted by the sun. Solar power is becoming more and more popular as a replacement for fossil fuel energy, and so most people can tell you at least this much. But how does a solar cell actually work? The answer is a bit more complex.
Also known as photovoltaic cells, solar cells are small, flat panels arrayed on the front of an electrical device. A good example is a calculator: the solar cells are represented on the face of the calculator as a small line of segmented, plastic panes on the top. It’s here that the light energy from the sun is collected and converted into electrical energy to power the calculator. Roughly the same process is used to power satellites in space that have solar panels, despite the size difference.
The composition of the cell is more complex than it looks at first glance. Encyclobeamia.net succinctly describes the layout of a typical, large-scale solar cell, which is composed of three layers in this order:
– A glass pane that allows light to pass through easily
– A layer of semiconductors used to trigger the photovoltaic process
– A layer of metal to collect and transmit the generated electrical energy
HowStuffWorks.com describes the process of collection: as the light hits the solar cells and goes through the glass it makes contact with the semiconductors (usually silicon) inside the solar cell, transferring the energy of the light to the semiconductors. During this process the electrons of the light energy are knocked free of their atoms, and are shunted via the metal plate at the bottom to the machine’s battery. This energy is then stored and used just like any other form of electricity.
Despite how efficient this process sounds, however, solar energy is notoriously difficult to capture. It does not come down in equal measures, and given the high reactivity of electrons a great deal of solar energy is typically lost in the process of collection – typically more than 80 percent, according to HowStuffWorks.com. Recent advancements in solar energy have, according to TechEye.net, pushed theoretical efficiency up above 40 percent, though there’s still a long way to go before solar cells absorb every bit of solar energy.
Is full efficiency worth the effort? Absolutely. CoolEarthSolar.com calculates that the sun provides enough energy every hour to power humanity’s electronics for a year. If mankind were able to harness all of that power, other, dirtier and potentially more harmful sources of electricity – fossil fuels and nuclear energy – would be immediately displaced. So long as the sun shines, there’s plenty of energy for everyone.
