Product Description

The United States is the leader in cadmium telluride (CdTe) photovoltaic (PV) manufacturing, and NREL has been at the forefront of research and development in this area. PV solar cells based on CdTe represent the largest segment of commercial thin-film module production worldwide. Recent improvements have matched the efficiency of multicrystalline silicon while maintaining cost leadership.
CdTe-based PV is considered a thin-film technology because the active layers are just a few microns thick, or about a tenth the diameter of a human hair. A schematic of a typical CdTe solar cell is shown here. Transparent conducting oxide (TCO) layers such as SnO2 or Cd2SnO4 are transparent to visible light and highly conductive to transport current efficiently. Intermediate layers such as CdS help in both the growth and electrical properties between the TCO and CdTe. The CdTe film acts as the primary photoconversion layer and absorbs most visible light within the first micron of material. Together, the CdTe, intermediate, and TCO layers form an electric field that converts light absorbed in the CdTe layer into current and voltage. Metal is placed on the back to form electrical contacts. In production, all these layers are deposited on incoming glass and processed into complete solar panels in just a few hours.