Thanks to photovoltaics, a field of science and technology dedicated to understanding and developing the application of converting solar energy into electricity, we are in a position to harness the energy produced by the sun. Don’t be fooled by its complicated name. A photovoltaic cell is just a device that converts the sun’s heat and light into usable energy. Or simply put, they are solar cells.

Photovoltaic and solar cells are everywhere, so much so that we often do not give them a second thought. From individual cells that power your calculator or wrist watch, to more complicated contraptions on highway signs and even on earth-orbiting satellites, solar cells are more ubiquitous and commonplace than you think.

A solar cell is actually much like a sandwich. It is composed of two layers of silicon that are specially constructed to allow electricity to be produced and flow in a desired way. The lower layer is called the p-type or positive-type silicon which is specially treated to contain a fewer number of the negatively-charged atomic particles called electrons. On the other hand, the upper layer is called the n-type or negative-type silicon has slightly more electrons. Electrons are crucial to the process, as it is the movement of these particles in a current that causes electricity to flow.

Now, sunlight is composed of tiny particles called photons. As photons enter this inedible sandwich, the laws of physical science set to work and something amazing happens. The photons give their energy to the silicon atoms in the lower layer, causing them to move around or become “excited.” This movement produces energy that causes the electrons from the p-type layer to jump across to the n-type layer. Since the n-type layer already contains far too many electrons, the extra ones are pushed out and flow on to the circuit, thus producing electricity.

So there you go – the workings of solar cells in a nutshell. So next time you pass by a reflective road sign or use your solar-powered calculator, you now know what makes them tick.

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