Fig. 1. Molecular structures of additives and their interaction with perovskite.

(A) Molecular structures of BZD and TFBZ. (B) Density functional theory (DFT) calculations of the adsorption energies between the FAI termination and BZD/TFBZ molecules. (C) DFT calculations of the adsorption energies between the PbI₂ termination and BZD/TFBZ molecules. (D) Partial enlarged view of the Fourier transform infrared (FTIR) spectra for TFBZ and BZD, as well as their mixtures with perovskite. (E) Partial enlarged view of ¹H nuclear magnetic resonance (NMR) spectra for BZD, TFBZ, and their mixtures with FAI and PbI₂ in DMSO-d₆ solvent. (F) X-ray photoelectron spectroscopy (XPS) spectra of Pb 4f and I 3d for perovskite films with and without TFBZ/BZD addition. a.u., arbitrary unit.