Interfaces of high-efficiency kesterite Cu_2ZnSnS(e)_4 thin film solar cells

Cu_2ZnSnS(e)_4(CZTS(e)) solar cells have attracted much attention due to the elemental abundance and the nontoxicity.However,the record efficiency of 12.6% for Cu_2ZnSn(S,Se)_4(CZTSSe)solar cells is much lower than that of Cu(In,Ga)Se_2(CIGS)solar cells.One crucial reason is the recombination at interfaces.In recent years,large amount investigations have been done to analyze the interfacial problems and improve the interfacial properties via a variety of methods.This paper gives a review of progresses on interfaces of CZTS(e)solar cells,including:(i)the band alignment optimization at buffer/CZTS(e)interface,(ii)tailoring the thickness of MoS(e)_2 interfacial layers between CZTS(e)absorber and Mo back contact,(iii)the passivation of rear interface,(iv)the passivation of front interface,and(v)the etching of secondary phases.