Enhancing the hydrophobicity of perovskite solar cells using C18 capped CH3NH3PbI3 nanocrystals

Abstract

An important limitation in the commercialisation of perovskite solar cells is lack of stability towards moisture due to fast degradation of the absorber perovskite layer. One approach to improve the stability is effective interface engineering by adding materials that can protect the underlying perovskite film. In this work, we look at the incorporation of C18 capped CH₃NH₃PbI₃ nanocrystals (MAPI NCs) in perovskite solar cells with both standard and inverted architecture. Three different solution-processing techniques were investigated and compared. We show that solar cells with MAPI NCs integrated at the perovskite–Spiro interface can reach over 10% efficiency. The presence of long chain ligands bound to the MAPI NCs does not appear to damage hole extraction. Most importantly, the hydrophobicity of the surface is significantly enhanced, leading to a much higher device stability towards moisture.