High-efficiency polycrystalline CdTe thin-film solar cells

Cadmium telluride is a promising photovoltaic material for thin-film solar cells. However, further improvements on performance and reproducibility of devices have been limited by the conventional SnO₂/poly-CdS/poly-CdTe device structure used for more than 30 years. In this paper, we review partial R&D approaches at NREL to understand the issues related to the conventional device structure and to develop several novel materials and a modified device structure for minimizing these issues. We have achieved a CdTe polycrystalline thin-film solar cell demonstrating an NREL-confirmed, total-area efficiency of 16.5% by using new materials and the modified device structure. To apply the high-efficiency CdTe cell fabrication technique, we developed two manufacturing processes for producing high-efficiency CdTe modules with the potential of high throughput and low cost.