The solar cells used in solar panels can be generally differentiated into three types – crystalline silicon solar cells, thin-film solar cells and a newish version that essentially conflates the two.
Crystalline silicon solar cells
Almost 090% of solar cells are manufactured from crystalline silicon, which are wafers that have been sliced off from big ingots that are purpose-grown in laboratories. It can take ingots an entire month to grow to sufficient size and they can assume the form of a single or multiple crystals.
The single crystals are used in the creation of monocrystalline solar panels and cells, whilst those with multiple crystals are made use of in polycrystalline panels and cells. An n-type ingot is used by these types of solar cells, which are created via heating chunks of silicon with a small amount of antimony, arsenic or phosphorus as the dopant. This is then partnered with a p-type silicon layer that makes use of boron as the dopant. The process that fuses the pair together in order to create a junction was devised nearly seventy years ago back in 1954.
Monocrystalline solar cells are identifiable by sight because of their striking appearance with a cylindrical shape and sometimes color. They provide a very high level of efficiency when used in solar panels, though their ability to be cut into shape can cause waste.
Polycrystalline cells on the other hand have no need for cutting, with the silicon instead being melted and then poured into square molds. These solar cells are often viewed as a mid-range option for solar panels in terms of both efficiency and price.
Thin film solar cells
Thin film solar cells are around 100 times thinner than crystalline silicon cells, which are made from wafers of less than a millimeter in depth already. These thin film solar cells are manufactured from amorphous silicon, which sees the atoms arrange in a random order rather than ordered as with crystalline.
The production of these cells comes via layering photovoltaics for the creation of a module and they are the cheapest option for making solar panel cells, capable of being laminated onto roofing tiles, skylights, windows and other substrates such as glass, polymers and metals. However these thin film cells produce just 7% efficiency in comparison to the 20% of crystalline silicon cells with even the best CIGS cells barely able to get to 12% efficiency.
Third generation solar cells
New solar cell technology has combined the best features from both thin film solar cells and crystalline silicon solar cells to create new solar cells with improved practicality and higher efficiency for use. These third generation solar cells are usually manufactured from amorphous silicon, perovskite crystals or organic polymers and come with multiple junctions that consist of layers of different semi-conductive materials.
Third generation solar cells can be more efficient and practical as well as cheaper than other solar cells and have reached 30% efficiency on occasion.
Solar power can help to cut electricity costs and reduce greenhouse gas emissions.