CdS/CdTe solar cells by the screen-printing-sintering technique: Fabrication, photovoltaic properties and applications

Abstract CdS/CdTe solar cells are fabricated on a borosilicate glass substrate by successively repeating screen printing and sintering (heating) in a belt furnace pastes of CdS, cadmium plus tellurium, carbon, silver plus indium and silver. In various sizes of solar cells, the highest efficiencies have been achieved for II–VI compound solar cells. The present solar cells have a spectral sensitivity up to a slightly longer wavelength than that of the usual CdS/CdTe solar cells. This may be due to the formation of CdSxTe1−x mixed crystals during the sintering of CdTe. In reliability tests under rooftop conditions, no remarkable change in the output power was observed in encapsulated solar cells over 800 days. From the results of accelerated tests on unencapsulated solar cells, a water-proof-type structure for the present solar cell module is required. The present solar cells and modules are now on the market for both indoor use and outdoor use; this is the first experience of the use of II–VI compound solar cells. Efforts to expand their application are being continued.