Two step solvent post treatment on PTAA for highly efficient and stable inverted

Modifying the surface of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) with toluene during the high-speed spin-coating process of dimethylformamide considerably improves the wettability and morphology of PTAA and results in improvement of the crystallinity and absorption of perovskite film.