Photovoltaic electric panels are composed mainly of silicon. Silicon is used because it naturally releases electrons (electrical energy) when hit with a photon (light source). The trick for photovoltaic manufacturers was to find a way to “catch” the displaced electrons and use their energy.

Most solar electric panels consist of a clear protective top layer, two layers of specially treated silicon with collecting circuitry attached to the top layer, and a tough polymer backing layer. From there, the panel can be framed (adds durability) or unframed (reduces weight), and in some cases the layers are even comprised of flexible materials. The vast majority of PV panels work in the same way:

The top layer of silicon is treated to give it an electrically negative character. The back layer is treated to make it electrically positive. Due to these treatments and added elements, the top layer is rich in electrons, and the back layer is relatively electron poor. These two layers are separated by an electrically charged junction, which allows electrons to flow from back to front, but not the other way around.

Photovoltaic solar power is created when light strikes the PV panel, some of the photons are absorbed by the silicon layers. The photons cause electrons to be released from the silicon crystal, and those electrons “wander around” looking for somewhere to attach themselves. Some of the electrons are freed from the bottom layer, and they find their way through the junction into the top (electron rich) layer. Some of the electrons are freed from the top layer, and since they cannot travel to the bottom (electron poor) layer, and are being “crowded” by new electrons from the bottom layer, they are left free to be collected by electrical contacts on the surface of the top layer.

Those collected electrons are routed through an external circuit, providing photovoltaic solar power to the electrical system attached to the panels. The circuit is completed when the electrons return to the bottom layer of the PV panel, find “resting spots” in the electron poor bottom layer, and wait for the next photon to shake them loose.

There are no moving parts in the PV panel, so maintenance is limited to keeping the junction boxes and wiring free from moisture and corrosion, and keeping the surface of the panel clean enough to allow light through to the silicon layers.

Related posts:

1. How does a photovoltaic cell produce electricity?
2. Anatomy of a Solar Cell
3. Energy Loss in a Solar Cell
4. How Silicon Makes a Solar Cell­
5. The Importance of Solar Power and Solar Panels

Tags: electrical energy, pv panels, solar power

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