Most solar cells are made of polycrystalline or monocrystalline silicon. Silicon is the most common metalloid because it is quite easy to process. It is also the eighth most common element in the universe by massand with strong semiconductor characteristics it is commonly used in solar panel manufacturing.
Silicon solar cells are made from silicon wafers. A silicon wafer is a thin slice of silicon crystal that is produced in several steps of a microfabrication process. For protection the slice has to be covered with a glass sheet. A silicon solar cell is usually put in a square form.
Polycrystalline Solar Cells
Polycrystalline solar cells are most common as the price efficiency correlation is quite good. Other types of solar cells may be more effective, but more expensive. A polycrystalline solar cell has an efficiency of approximately 11-14%.
Monocrystalline Solar Cells
Monocrystalline solar cells have higher efficiency rates than their polycrystalline counterparts. The production is more complex and makes a monocrystalline solar cell more expensive than others.
Thin Film Solar Cells
A thin film solar cell is also slightly more expensive, but has some significant advantages to other solar cells; they are made out of lighter materials and are better suited for roofs which cannot endure heavy weight. Another advantage is the high efficiency rate in diffusing sunlight. Thin film solar cells are therefore better suited for areas with less direct sunlight or roofs which do not face south.
There have been emerging photovoltaic technologies where different materials have been tested such as organic solar cells, which are also known as plastic solar cells. This technology is still under development and these particular organic solar cells still have low efficiency rates.