fig2

Figure 2. (A) Schematic illustration of the pyridine-based flush process for removing physisorbed multilayers from the SAM-coated ITO surface. From top to bottom, the first arrow corresponds to the “7H-dibenzo[c,g]carbazole unit”, the second arrow corresponds to the “Alkyl spacer chain”, and the third arrow corresponds to the “Phosphonic acid anchoring group”; (B-D) AFM topography images of SAM surfaces: (B) control (dip-coated only), (C) after 3-FPy post-treatment, and (D) after 3-MeOPy post-treatment; (E and F) ESP maps (top) and corresponding molecular structures (bottom) of (E) 3-FPy-4PADCB and (F) 3-MeOPy-4PADCB dimers; (G) DFT-calculated removal energies for displacing adsorbed 4PADCB using 3-FPy and 3-MeOPy. ITO: Indium tin oxide; SAM: self-assembled monolayer; 4PADCB: 4-(7H-dibenzo[c,g]carbazol-7-yl)butyl phosphonic acid; ESP: electrostatic surface potential; DFT: density functional theory; 3-FPy: 3-fluoropyridine; 3-MeOPy: 3-methoxypyridine.