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What Is Cadmium Telluride, and Why Do We Use It?
Cadmium is a metallic element that is naturally present in the water and soil. A by-product of zinc, lead, and copper mining, cadmium is frequently used because it has highly desirable chemical and physical properties, including a resistance to corrosion and chemicals, a tolerance for high temperatures, a low melting point, and excellent electrical conduction. Tellurium, a semi-metallic element, is combined with cadmium to produce the compound cadmium telluride, or CdTe.
CdTe is a technology of choice for use in thin-film photovoltaic modules because its physical characteristics make it an ideal material for the production of solar cells. CdTe has an almost perfect bandgap for solar energy conversion and can be made well by a variety of low-cost methods. Researchers at the National Renewable Energy Laboratory (NREL) predict that small-area CdTe cells may reach about 19% efficiency in the next five to ten years, and modules will be available at a low cost to consumers. This cost reduction would provide a pathway for PV to become an important part of the world's electricity supply.
Although CdTe has tremendous value in commercial PV applications, some have concerns about health risks associated with its improper use in manufacturing and residential applications. Others share concerns about its safe disposal at the end of the PV module's useful life. However, the very real environmental and health benefits of using CdTe to make solar electricity must be carefully weighed against the perceived risks.
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