Germanium-based wide band gap kesterite semiconductor Cu2ZnGe(S,Se)4 (CZGeSSe) is considered a very promising absorber compound as top cell in tandem devices. Autonomy to tailor the from ~1.47 eV (Cu2ZnGeSe4-CZGeSe) ~2.2 (Cu2ZnGeS4-CZGeS), well non-toxic constituents makes this strong candidate for further scientific exploration. However, record efficiency of Cu2ZnGeSe4 solar cells still signif...
