Interface-suppressed high-quality symmetrical bifacial flexible CZTSe solar cells through a green electrodeposition process

Bifacial flexible solar cells are considerably attractive owing to their high generation of energy per area and multidirectional light irradiation in advanced applications, such as building-integrated photovoltaics. Their technological ability to reduce manufacturing costs and time is highly essential. Although the solution-processed technique has implemented bifacial flexible Cu2ZnSn(S,Se)4 (CZTSSe) solar cells, no progress on the green electrodeposition process has occurred. Herein, we first propose symmetrical bifacial Cu2ZnSnSe4 (CZTSe) solar cells through a facile electrodeposition process, in which Mo foils are used as a common back electrode for both sides. Stacked electrodeposition accomplished at one time is involved to produce high-quality bifacial CZTSe absorber layers. This strategy can guarantee the consistency of bifacial flexible solar cells and immensely low costs and time. The resultant high efficiencies of 6.43% and 6.20% for the two sides have made a great breakthrough for electrodeposited flexible CZTSSe devices and offered a cost-effective strategy for green-processed material fabrications. Compared with the solution-processed technique, the determined interfacial-suppressed Voc limiting the efficiency provides a clear aspect for further improving the efficiency. A symmetrical bifacial flexible Cu2ZnSnSe4 (CZTSe) solar cells are fabricated through a green electrodeposition process with championed efficiencies for both sides.