The effect of Ag incorporation on the phase stability, crystallinity and band structure on the (Cu,Ag)2ZnSn(S,Se)4 kesterite solar cells

The effect of Ag incorporation on the kesterite CZTSSe thin film by vacuum process has been investigated aiming for the band engineering of the kesterite solar cells. Phase stability, crystalinity, morphology and optical properties of Ag₂ZnSnSe thin film were firstly reported and measured by XRD, SEM and UV-visible spectrometer in this work. We have successfully fabricated the ACZTSe thin films over a wide range of composition and the optical band gap could be controlled by the Ag/(Cu+Ag) ratio in a range from 1.06eV to 1.3 eV. Finally, the cell performance around 4% was demonstrated by the ACZTSSe devices.