Probing Band-Alignment at the Interface of 3D/2D Perovskites for Solar Cell Applications

In this report, the effect of interfacial band-alignmentin 3D/2Dperovskite heterostructures on the performance of solar cells hasbeen studied. The heterostructures have emerged as a preferred approachto slow down the degradation of 3D perovskites. We have incorporatedthree different organic spacers, namely butylammonium (BA(+)), phenethylammonium (PEA(+)), and ethanolamine (EA(+)), in forming the 2D perovskite layer over the top of a 3Dtriple-cation halide perovskite. The power conversion efficiency hasbeen found to depend on the 2D perovskite. The band-energies of the3D and the 2D perovskites, derived from scanning tunneling spectroscopyand Kelvin probe force microscopy, have showed that the EA(+)-based capping layer forms a type-II band-alignment at the 3D/2Dinterface and thereby facilitates charge separation. Our work depictsthe necessity of probing the interfacial band-alignment while fabricatingsolar cells based on 3D/2D perovskites.

Automated summary

In this study, the impact of interfacial band-alignment on the performance of 3D/2D perovskite heterostructures in solar cells was investigated. Using different organic spacers, the efficiency of the solar cells was found to be dependent on the 2D perovskite layer. The formation of a type-II band-alignment at the 3D/2D interface facilitated charge separation. This research highlights the importance of probing the interfacial band-alignment when fabricating solar cells based on 3D/2D perovskites.