Technological status of Cu2ZnSn(S,Se)4 thin film solar cells

This report gives an overview of the technological status of thin film solar cells based on kesterite absorber materials Cu2ZnSn(S,Se)4 (CZTSSe), pure sulfide Cu2ZnSnS4 (CZTS) and selenide Cu2ZnSnSe4 (CZTSe). As an alternative absorber material for thin film solar cells, CZTSSe has gained a lot of research interest due to its suitable physical properties and utilization of more earth abundant elements. Different methods are used for the growth of CZTSSe absorber layers and remarkable progress has been made in solar cell efficiency. The majority of research laboratories and companies use the following device structure: soda lime glass substrate/Mo back contact/ CZTSSe absorber/CdS buffer/i-ZnO/ZnO:Al window layer. In order to give an overview of “mature” representative methods and materials, only selected examples with efficiencies≥6% are summarized in Table 1 and the status of industrial efforts is given in Table 2. Please note that this report or the given data herein make no claim on completeness or comprehensive coverage of all the important research and development efforts in the field, the authors have used their discretion to present selective examples for the status report.