Characterization of Cu2ZnSnSe4 solar cells prepared from electrochemically co-deposited Cu-Zn-Sn alloy

Cu-Zn-Sn (CZT) precursors for Cu2ZnSnSe4 (CZTSe) solar cell were prepared by electrochemical co-deposition method with different metals composition. CZT precursors were preliminary annealed in three different atmospheres in order to obtain homogenous, without pores Cu-Zn-Sn layers. A high crystalline quality CZTSe absorber was synthesised as has been determined by X-ray diffraction and Raman spectroscopy methods. CZTSe based solar cells were fabricated and champion cell demonstrated 2.7% efficiency and reached as high as 70% of external quantum efficiency. Scanning electron microscope investigations of CZTSe solar cells cross-section revealed that Mo/CZTSe interface exhibits large voids and local delamination from Mo layer. The back contact issues are detrimental to solar cell performance reducing shunt resistance and open circuit voltage.