High efficiency bifacial Cu2ZnSnSe4 thin-film solar cells on transparent conducting oxide glass substrates

摘要

In this work, transparent conducting oxides (TCOs) have been employed as a back contact instead of Mo on Cusub2/subZnSnSesub4/sub (CZTSe) thin-film solar cells in order to examine the feasibility of bifacial Cusub2/subZnSn(S,Se)sub4/sub (CZTSSe) solar cells based on a vacuum process. It is found that the interfacial reaction between flourine doped tin oxide (FTO) or indium tin oxide (ITO) and the CZTSe precursor is at odds with the conventional CZTSe/Mo reaction. While there is no interfacial reaction on CZTSe/FTO, indium in CZTSe/ITO was significantly diffused into the CZTSe layers; consequently, a SnOsub2/sub layer was formed on the ITO substrate. Under bifacial illumination, we achieved a power efficiency of 6.05% and 4.31% for CZTSe/FTO and CZTSe/ITO, respectively.