Cadmium telluride (CdTe) photovoltaics are used in some of the world’s largest photovoltaic power stations, such as the Topaz Solar Farm. CdTe has long been well known as a leading thin-film PV material due to its near optimum bandgap of 1.44 eV and high absorption coefficient.
CdTe solar cells have quietly established themselves as a mass market PV technology. Despite the market remaining dominated by silicon, CdTe now accounts for around a 7% market share and is the first of the second generation thin film technologies to effectively make the leap to truly mass deployment. CdTe thin-film solar cells can be manufactured quickly and inexpensively, providing an alternative to conventional silicon-based technologies. The record efficiency for a laboratory CdTe solar cell is 22.1%, and its average commercial module efficiency to be approximately 18% at the end of 2020.
On a lifecycle basis, CdTe PV has the smallest carbon footprint, lowest water use and shortest energy payback time of any current photo voltaic technology. CdTe’s energy payback time of less than a year allows for faster carbon reductions without short-term energy deficits, and can last anywhere from 25 – 30 years.
The benefits of CdTe thin-film solar cells include:
High absorption: Cadmium telluride is a direct-bandgap material with bandgap energy that can be tuned from 1.4 to 1.5 (eV), which is nearly optimal for converting sunlight into electricity using a single junction.
Low-cost manufacturing: Cadmium telluride solar cells use high throughput manufacturing methods to produce completed modules from input materials in a matter of hours.