Why Are Solar Panel Blue?

December 23, 2021

Most solar car battery chargers have blue solar panels. Although blue is the majority, you can also see some black solar panels depending on the respective manufacturing method.

As you know, black is the color that absorbs the most light. So why are most solar panels blue in color? Polycrystalline silicon solar panels are in the majority, so when most people hear the word "solar", they think of a few blue rectangular panels.

Understanding the color of solar panels requires us to study the materials they are made of. Interestingly, almost all commercially used photovoltaic cells are made of silicon.

Silicon (Si) and its compounds have countless applications in glass, cement, electronic components, and more. As a semiconductor material, silicon itself has a blue hue and a metallic gray luster.

Pure raw silicon

There are three main types of silicon cells, depending on the manufacturing method. The most common type is the polycrystalline cell, which has a distinct blue color.

The second type is monocrystalline, which is made from a single large silicon crystal. Monocrystalline cells have a black or almost black hue. There are other, lesser-used types, such as thin-film, which also have a color close to black.

Anti-reflective coatings

As one might guess from the name, it is a coating that covers the panel to reduce the reflection of incident sunlight. However, the coating changes the way light waves interact with the glass on top of the panel. This causes the color of the panel to look slightly bluish.

Color and Efficiency

Despite the importance of polycrystalline silicon solar panels in the global market, black is still the more efficient color. That is, monocrystalline solar car battery chargers are more efficient.

Finally, we can say that not all solar chargers have blue panels, but the most common is certainly blue. As we know from the above, this is due to the polycrystalline silicon and AR coating.

As technology advances, the color may shift heavily to black to facilitate efficiency. The premise is that the cost can be kept low in manufacturing. However, if the preference happens to be for aesthetics rather than efficiency, then the color panels under study are worth considering.