CdTe thin film technology: Leading thin film PV into the future

CdTe is a near perfect material for PV application with a direct band gap of ∼1.5 eV that is closely matched to the terrestrial solar spectrum and a high optical absorption coefficient where less than 1 μm thickness is adequate to absorb the incident light. CdTe thin film solar cell and module technology has validated the economies of scale that were projected for thin film PV technologies since the early 1980s where manufacturing costs are now below $0.84 with module efficiencies of 11.1%. Additionally, the low-temperature coefficient of CdTe modules results in a high annualized output. A critical issue for CdTe manufacturers is that there is not a clear pathway to increase the module performance to 15% or beyond based on current laboratory results and efficiency improvements will require fundamental improvements in the CdTe semiconductor properties and/or developing an alternative device structure.