What is a solar cell?

What is a solar cell and how does it work?

A solar cell is able to absorb the photon energy from the sun and deliver electrical power. Electrical power is current and voltage.

Solar cells are made of the same kinds of semiconductor materials, such as silicon, used in the microelectronics industry. For solar cells, a thin semiconductor wafer is specially treated to form an electric field, positive on one side and negative on the other. When light energy strikes the solar cell, electrons are knocked loose from the atoms in the semiconductor material. If electrical conductors are attached to the positive and negative sides, forming an electrical circuit, the electrons can be captured in the form of an electric current – that is, electricity. (1)

An electrical circuit

So, when everything is in place and light energy hits a solar cell, an electrical circuit is formed.

At present, solar photovoltaic energy provides 1% of all electricity usage globally. On average, one square metre of land receives the equivalent energy per year as a barrel of oil or 200 kg of coal. (2)

We know that the sun provides us with enormous energy, but how do we convert that into usable electricity to power our homes, cars and devices?

How we convert energy into useable electricity

We use solar panels. Solar panels are comprised of dozens of solar cells, wired together to generate a large enough electrical output.

By the time you have combined hundreds, thousands, if not millions of solar panels together, you end up with complexes large enough to meet the electricity needs of a million or more people, like in the Pavagada solar park in India.

References

1. Richard Komp, TED-Ed, How do Solar Cells Work? [cited 15 October 2019]. Available from: TED-Ed (Web link)
2. Solar [Internet]. Worldenergy.org. 2019 [cited 10 May 2019]. Available from: World Energy (Web link)