Thin Film vs Traditional Silicon Solar Cells
What Are Solar Cells?
Solar cells, or photovoltaic (PV) cells, utilize semi-conductors that conduct electricity when heated by the sun and/or combined with other materials. Most solar applications utilize traditional silicon solar cells, however, thin-film solar cells are finding a respectable niche in the solar market.
What Are Traditional Silicon Solar Cells?
Silicon solar cells are the traditional type of PV cells used in solar technology. Silicon serves as the semi-conductor, with light-absorbing layers 350 microns thick. (One micron is 1 millionth of a meter.) In theory, this technology should be able to convert into electricity as much as half of the energy striking the solar cells. However, the energy conversion is more often 15 to 25 percent.
What Are Thin Film Solar Cells?
Thin film solar cells are made from one of three semi-conducting materials:
- Amorphous Silicon (a-Si) is essentially a mini-version of the traditional silicon solar cell technology. The least efficient of the thin-film solar cells, a-Si is best-suited to small-scale applications, like calculators.
- Cadmium Telluride (CdTe), though energy efficient, poses an environmental hazard as cadmium is highly toxic and can accumulate in food chains.
- Copper Indium Gallium Diselenide (CIGS) is the most energy efficient of the thin-film technologies. However, it is also the most variable, as it utilizes four metal alloys and processes that leave a lot of room for impurities to interfere with quality.
As the name implies, thin-film solar cells are extremely thin at just 1 micron thick, compared to the 350 micron thickness of traditional silicon cells. Thin-film solar cell efficiency levels vary. For instance, CdTe solar cells may get as much as 15 percent efficiency, and CIGS as much as 20 percent, though levels may also be significantly lower depending on the manufacturer and manufacturing process.
What Are the Advantages of Thin Film Cells?
When compared to traditional silicon solar cells, thin-film cells are:
- Less expensive to produce via a comparatively simpler manufacturing process, at one half the cost of traditional silicon cells.
- More flexible, lightweight and durable, presenting a wider range of design possibilities.
- Easier to install than traditional silicon cells.
What Are the Advantages of Traditional Silicon Cells?
When compared to thin-film solar cells, traditional silicon cells are:
- More efficient, producing twice as much energy as thin-film.
- Require significantly less space to produce the same amount of energy.
- Less reliant on materials from outside the U.S., as thin-film cell manufacturing sources metals from overseas, particularly China.
Who Are the Biggest Players in the Thin Film Solar Cell Market?
FirstSolar is the world's leading producer of thin-film solar cell technology. However, GE is building the largest solar panel factory in the U.S. where it will manufacture what is reportedly the most energy efficient thin-film solar technology in the world.