Solar panels are one of the biggest sources of renewable, green energy in the world. Their long lifespan, scarce need for maintenance and ease of installation make them the perfect choice for domestic use. There are different types of solar panels you can choose from, each with different features and separate production processes.
The two main types are crystalline solar panels and thin film (or amorphous) panels. Both are manufactured using silicon, a semiconductor material that is easily found in nature, making up almost 30% of the Earth’s crust. It comes in two forms, amorphous and crystalline, which are respectively brown and dark in color.
Crystalline Solar Panels
A distinction must be made between polycrystalline and monocrystalline solar panels. Growing a large, single crystal is more expensive than combining smaller multiple crystals, so the panels made of monocrystalline cells are usually more expensive.
These two types of cells are easy to look apart: black cells with rounded angles are monocrystalline, while blue, rectangular cells are polycrystalline. Even though monocrystalline panels are usually more expensive and efficient, with recent advances in technology the gap has significantly shrunk and often well-made polycrystalline cells perform better than their competitors.
A crystalline solar panel is made up of different cells enclosed in a frame. These cells are manufactured by cutting disks (wafers) made of crystalline silicon, not thicker than 1cm. After being cut, they are polished and holes are filled to make the wafer uniform. The pure silicon has to be “contaminated” in order to be able to produce electricity.
Usually that is done by adding a layer of phosphorous and heating the surface, so that the phosphorous atoms can diffuse throughout the wafer. After that, the “doped” wafers are aligned to make the solar cells, which are successively arranged on a panel. The metal grid you can see on the surface of the panel is made of conductive metal strips. The final step is to add a glass layer to protect the panel from the elements without blocking the sunlight.
Thin Film (or Amorphous) Solar Panels
The main difference between crystalline and amorphous silicon panels is that instead of being composed of different cells assembled together, thin film panels are made of a single layer of silicon that is laid upon a backing material. This can be either a flexible (plastic) or rigid material (glass or metal), which makes thin film a much more versatile technology.
Moreover, a lot less material is used in their production, making them much cheaper than crystalline panels, but with a reduced solar efficiency. Due to this difference, thin film solar panels occupy much more space than their competitors to produce the same amount of electricity, although they are less affected by shading.
Since the whole layer is produced in one go, these panels are much easier to manufacture and assemble. The latest innovations in thin film have led to multijunction solar panels, which contain several layers of silicon that absorb sunlight differently, thus capturing the whole light spectrum.
Read more: Types of Solar Panels