Graphene protection improves the stability of two-dimensional halide perovskites under the electron irradiation.

The crystal structure of two-dimensional (2D) organic-inorganic halide perovskites undergoes fast structural collapse under the electron beam irradiation, hindering high-resolution transmission electron microscopy imaging. Graphene protection is an effective solution to mitigate the damage of electron-beam irradiation and has been applied in 2D materials such as MoS 2 . However, the effectivity of graphene protection has not been demonstrated in 2D halide perovskites yet, as traditional wet-transfer of graphene with aqueous solution would cause serious degradation for moisture-sensitive halide perovskites. Here, we verified that graphene protection plays a protection role and developed a method using nonpolar solvent to transfer the graphene layer atop the perovskite nanosheets. With this method, the perovskite nanosheets might be well protected by graphene encapsulation. HIGHLIGHTS: Transfer method of graphene on moisture-sensitive 2D halide perovskites using nonpolar solvents was developed. Graphene substrate is proven to be able to mitigate electron-beam damage to 2D halide perovskites. Encapsulation structure of graphene/halide perovskite/graphene was demonstrated.