Photovoltaics – this is where it all starts. Let’s look at a brief, summarized history…
This technology, commonly shortened to PV, has its roots in 19th Century France. Alexandre-Edmond Becquerel, a French physicist, discovered the photovoltaic effect in 1839. This effect is simply the production of electricity from sunlight. Becquerel effectively created the first solar cell using selenium as a semiconductor.
Although some improvements were made in solar cell technology since the mid-19th century, it wasn’t until the late 1950’s that the first conventional solar cell was produced by Bell Laboratories. This major development occurred when they created a diffused silicon p-n junction. This increased the efficiency of the cell from 0.5% to 6%. By 1960, cells were developed that achieved 14% efficiency.
PV technology has since been used to power everything from calculators to satellites. Improvements in PV technology (and the industry) continues to drive down prices and increase overall solar cell efficiency percentages.
Now that we have considered some basic history of photovoltaics, let’s look at what makes up a solar cell and how it generates electricity.
A simple solar cell has five parts (see diagram below); anti-reflection coating, front contact, emitter (n-type semiconductor), base (p-type semiconductor), and the rear contact.
Electricity is generated in a three step process;
1. Sunlight hits the cell creating an electron-hole pair.
2. The electron moves from the emitter through the external circuit – passing on its energy.
3. Completing the circuit, the electron reconnects with the hole in the base.
To learn about how solar cells are used to create PV systems, check out the solar panels page.