Silicon solar cells are often referred to as wafer-based bulk technology.
Each form of bulk technology manufacture consists of self-supporting silicon wafers of between 180 to 240 micrometers thick.
The wafers are processed and then connected together to form a solar cell module (solar panel).
A description of the types of bulk silicon cells is provided below.
Crystalline Silicon Cells
Crystalline silicon - also known as "solar grade silicon" - is the most abundant bulk material available for solar cell production.
Bulk silicon is categorized according to crystallinity and crystal size in the silicon wafer, ribbon or ingot.
This video offers a much deeper understanding of the solar cell process. It is quite involved and runs for about 20 minutes - so grab a cup of coffee and prepare to be highly informed!
Mono-crystalline Silicon
A single-crystal silicon - often made using the Czochralski process - mono-crystalline wafer cells are generally expensive.
The expense arises as mono-crystalline wafers are cut from cylindrical ingots.
As a result, the silicon wafers do not entirely cover the surface of a square solar cell module without a substantial waste of refined silicon. Hence most mono-crystalline panels have uncovered gaps at the four corners of the cells.
Ribbon Silicon
Ribbon silicon is a type of mono-crystalline silicon.
It is made by drawing flat thin films from molten silicon that has a multi-crystalline structure.
These cells are less efficient than poly-crystalline silicon, however a huge reduction in silicon waste means production costs are significantly lower.
Poly-crystalline Silicon
Made from cast square ingots, poly-crystalline silicon (also known as multi-crystalline silicon) cells are less expensive to produce than single-crystal silicon cells.
The trade off however, is that they are less efficient.
US DOE data shows that there were a higher number of multi-crystalline sales than mono-crystalline silicon sales. This indicates that consumers are still leaning towards lower installation costs than potentially higher energy savings.
That said, whilst theoretical efficiencies differ, all types of crystalline silicon cells operate at an average 15% efficiency.
That sums up the types of bulk silicon solar cells. Now read about thin film solar cells.
