3.2.3 Thin-film silicon PV
Solar cells can also be made from very thin films of silicon, in a form known as amorphous silicon (a-Si), in which the silicon atoms are much less ordered than in the crystalline forms described above.
Amorphous silicon cells are much cheaper to produce than those made from crystalline silicon, and are also better absorbers of light, so thinner, and therefore cheaper, films can be used.
There are also advantages in the manufacturing process:
- it operates at a much lower temperature than that for crystalline silicon, so less energy is required
- it is suited to continuous production
- it allows quite large areas of cells to be deposited onto a wide variety of both rigid and flexible substrates, including steel, glass, and plastics.
However a-Si cells are currently much less efficient than their single-crystal or polycrystalline silicon counterparts. Commercially available a-Si modules achieve stable efficiencies in the range of 4% to 8%, and are already widely used as power sources for a variety of consumer products, such as calculators, where the requirement is for low cost rather than high efficiency.
Now you’ll look at other thin-film PV technologies.