Formation of 2,2′-bipyridine adlayers at Sb(111)|ionic liquid + 2,2′-bipyridine solution interface

•2,2′-Bipyridine adsorption from ionic liquids•Good agreement between modeled and measured EIS and in situ STM data•Influence of potential and polarization time on 2,2′-bipyridine adsorption layer structure

In situ scanning tunneling microscopy (STM), cyclic voltammetry and electrochemical impedance spectroscopy methods have been applied to study the adsorption of 2,2′-bipyridine (2,2′-BP) on Sb(111) single crystal electrode surface from 1-ethyl-3-methylimidazolium tetrafluoroborate + 1% 2,2′-BP solution. Influence of the Sb(111) electrode potential on the adsorption characteristics of 2,2′-BP has been demonstrated. The in situ STM data revealed that 2,2′-BP forms highly ordered patterns on the Sb(111) single crystal electrode surface. The formed dense organic adlayer decreases the dielectrical permittivity of the interface, acting as a dielectric capacitor with significantly lower characteristic relaxation time than the pure ionic liquid system.