A highly hydrophobic fluorographene-based system as an interlayer for electron transport in organic-inorganic perovskite solar cells

Abstract

Degradation of perovskite halide materials under humid conditions is one of the major hurdles in the commercialization of organic-inorganic perovskite solar cells. Herein, we studied the interface between highly hydrophobic fluorographene (FGr) and cubic methylammonium lead iodide (MAPbI3, MA: CH3-NH3) by employing density functional theory (DFT)-based simulations. We demonstrate that the adsorption of FGr on MAPbI3 results in the formation of a stable interface with appreciable binding energy (∼0.4 eV per Pb atom). Thorough assessment of energy-level alignment indicates that the FGr/MAPbI3 interface has desirable properties with regard to the electron transfer (hole blockage) process. These results underscore the potential of using FGr as an interlayer for electron transport between a perovskite layer and an electron transfer medium (such as TiO2) as well as a moisture blocker for achieving high perovskite stability by perfect waterproofing. The future research study towards the integration of hydrophobic FGr or electronically optimized partially fluorinated graphene-based systems within perovskite halide photovoltaic devices may pave the way for stable and efficient solar cell technologies.