Progress in CuInS2 submodules

Photovoltaic devices of different size based on CuInS₂ thin film absorbers have been prepared with a layer structure glass/Mo/CuInS₂/CdS/ZnO. The CuInS₂ absorber layers have been grown by a sequential process consisting of DC sputter deposition of copper and indium followed by sulfurization in elemental sulfur vapor. Total area efficiencies of 11.4 % and 9.4 % have been reached on 0.5 and 6.2 cm² single cells, respectively. A 16.2 cm² submodule with 7 integrated series connected cells on a 5×5 cm² glass substrate reached 9.2 % efficiency under AM 1.5. The superior performance of the smaller area devices is mainly due to better fill factor while the open circuit voltage of the submodule reaches 5.1 V which is the sevenfold value of the single cell devices. A lower short circuit current of the submodule compared to single cells is due to loss of active area by the integrated series connection. Single module cells of different width without grid but with ZnO of different thickness have been used for module optimization