SILAR films of p-type Cu2FeSnS4 (CFTS) introduced in pn-junction solar cells. A range of chalcogenides used as n-type compound semiconductors. Both components of the junctions were SILAR films formed under atmospheric condition. Band-edges of the semiconductors were located from density of states (DOS). Type-II band-alignment of the pn-junctions and energy conversion efficiency of the solar cells were correlated.