CdTe thin film solar cells : present status and future perspectives

The CdTe thin film solar cells have reached enough technological maturity to be one of the most successful photovoltaic technologies in the market. From the early stage of research, in the eighties, up to now, CdTe solar cells have provided a constant increase in efficiency together with a more effective fabrication process that reduces the amount of material and increases the industrial scalability, due to the large variety of the fabrication processes and to the robustness of the material.In the last 10 years, different key issues from the recrystallization/activation treatment (enhancing CdTe grain size and passivating the grain boundaries) to the back contact stability (incapsulating copper into a stable compound) have been deeply studied and engineered. With these advances the CdTe photovoltaic technology has now the lowest cost per Watt available, due to the low amount of material involved, the low energies used in the fabrication process and the fast all-in-line production with monolithical integration of the solar cells. In this paper, recent technologies for CdTe thin film solar cell fabrication are shown, low temperature and high temperature deposition processes in the laboratory and on the industrial scale, together with the monolithical integration, together with some environmental considerations are described.