20% Efficient Perovskite Solar Cells with 2D Electron Transporting Layer

Herein, a 2D SnS₂ electron transporting layer is reported via self-assembly stacking deposition for highly efficient planar perovskite solar cells, achieving over 20% power conversion efficiency under AM 1.5 G 100 mW cm⁻² light illumination. To the best of the authors' knowledge, this represents the highest efficiency that has so far been reported for perovskite solar cells using a 2D electron transporting layer. The large-scaled 2D multilayer SnS₂ sheet structure triggers a heterogeneous nucleation over the perovskite precursor film. The intermolecular Pb⋅⋅⋅S interactions between perovskite and SnS₂ could passivate the interfacial trap states, which suppress charge recombination and thus facilitate electron extraction for balanced charge transport at interfaces between electron transporting layer/perovskite and hole transporting layer/perovskite. This work demonstrates that 2D materials have great potential for high-performance perovskite solar cells.