Fig. 1: DFT calculation, schematic diagram and surface potential.

a Molecular structure, gaussian calculated ESP and molecular dipole of 2DPAA. b Gaussian structure optimized interfacial dipole moment and orientation of the Me-4PACz and Me-4PACz/2DPAA sample. c Schematic diagram of Me-4PACz adsorption on the substrate with and without 2DPAA treatment. d The optimal conformation of the bimolecular model adsorbed on the substrate (the arrow is the whole dipole orientation). e, f KPFM images of the control and 2DPAA-treated perovskite film at the buried interface. g CPD changes of both buried perovskite films.