Monolithic CZTS/Si tandem cells: development of multilayer structures for the intermediate contact

Cu ₂ ZnSnS ₄ (CZTS) wide-bandgap semiconductor can find a promising application in CZTS/Silicon tandem devices. The connection between the top and the bottom cells requires development of a proper intermediate electrical contact that must exhibit high transparency in the infrared region, chemical stability under thermal treatment and must prevent silicon degradation during the sulfurization processes used for the CZTS growth. In this work we report a first CZTS/Silicon monolithic tandem device with a V _oc = 948 mV and an efficiency of 3.5%, produced using a MoS ₂ /FTO/ZnO intermediate contact. This trilayer needs to be optimized to increase the J _sc still limited to 6 mA/cm ² .