Non-fullerene-based small molecules as efficient n-type electron transporting layers in inverted organic–inorganic halide perovskite solar cells

We introduce that a solution-processed small molecule ITIC can effectively function as the ETL for the fabrication of high-performance organic–inorganic hybrid perovskite solar cells (PeSCs). The role and effect of ITIC on device performances was studied using field emission scanning electron microscope, surface potential image, atomic force microscopy, and internal resistances in PeSCs. As a result, we finally achieved a high PCE of 11.94% in the PeSC with an optimum ITIC comparable with the PCBM-based device. This approach suggests that non-fullerene small molecules ITIC could be considered as a promising interfacial material for achieving highly efficient PeSCs.