Fig. 3: Design of passivators.
From: The dynamic adsorption affinity of ligands is a surrogate for the passivation of surface defects
a Molecular structures of three passivator molecules (FSA, APSA and 4-ABPA). Gaussian calculated electrostatic potentials (φ, ESP) values of maximum ESP (φmax) and minimum ESP (φmin) are also shown. φmax and φmin values are obtained using Multiwfn code38. b Binding energy of three molecules with the AI-terminated (001) surface of MAPb0.5Sn0.5I3 and MA0.25FA0.75Pb0.5Sn0.5I3. c ab initio molecular dynamics (AIMD) snapshots of bare, APSA, and 4-ABPA adsorbed perovskite surface exposure to oxygen and moisture conditions at a temperature of 400 K. The perovskite composition is MA0.25FA0.75Pb0.5Sn0.5I3. P atoms, lavender color; S atoms, yellow color; O atoms, red color; Pb atoms, gray color; Sn atoms, orange color; I atoms, purple color; N atoms, green color. d The number of adsorbed ligands for APSA and 4-ABPA at the conditions shown in Fig. 3c from 4 ps to 12 ps during the AIMD simulation. Ligand number of 16 represents complete surface coverage within the simulation unit. Blue line: APSA adsorption case; Red line: 4-ABPA adsorption case. The average value of adsorbed ligands during the last 2 ps of the AIMD simulation for APSA and 4-ABPA are 8 and 11, respectively. e Temperature-programmed desorption mass spectrometry (TPD-MS) of control and 4-ABPA treated FA0.75MA0.25Pb0.5Sn0.5I3 perovskite films. f Characteristic mass spectrum (m/z) peaks of control and 4-ABPA treated perovskite films.
