Probing the Local Conformation within π‐Conjugated One‐dimensional Supramolecular Stacks using Frequency Modulation Atomic Force Microscopy

Local contact potential difference of molecular self-assemblies investigated by Kelvin probe force microscopy

“…4(a)-4(c)), for which the topographic and dissipation images display identical contrasts than the ones reported in our previous works. 16,19 Particularly, the dissipation (Fig. 4(b)) is higher over the wires with the C¼O bond pointing downward (the molecular electric dipole being oriented upward), consistently with Qplus AFM investigations 19 carried out in the low amplitude regime.…”

“…7 nm) with respect to the single nanowire width. 16 On the contrary, FG1 assemblies (Figs. 1(e) and 1(f)) are formed by identical molecular wires (all C¼O bonds pointing upward), 17 the lattice periodicity (ca.…”

“…1(d)), which synthesis has been described elsewhere. 14,15 When deposited from solutions on HOPG, both molecules self-assemble into edge-on pi-conjugated nanowires stacks, which structural organization has been established by combining the results of NC-AFM with molecular mechanics (MM) and molecular dynamics (MD) simulations (see our former report 16 for QTF8, and the supplementary information 17 for FG1). After in-situ annealing, QTF8 stacks (Figs.…”

“…After in-situ annealing, QTF8 stacks (Figs. 1(b) and 1(c)) consist in non-polar layers 16 in which the orientation of the fluorenone unit (carrying the main molecular electric dipole) alternates from one wire (C¼O bond pointing upward) to the next (C¼O bond pointing downward), leading to a doubling of the lattice periodicity (ca. 7 nm) with respect to the single nanowire width.…”

“…4.5 nm) being slightly larger than the width of a single molecule due to a partial adsorption of the alkyl side groups on the graphite. NC-AFM/KPFM experiments were carried out at room temperature in UHV using a VT-beam AFM system 2,16 and in situ annealed PtIr 5 coated Si cantilevers (Nanoworld, typical spring constant k of 2.8 Nm À1 ). Topographic imaging was performed in the frequency modulation mode (FM-AFM), and KPFM data were simultaneously recorded in the amplitude modulation mode (AM-KPFM) with a bias modulation of 100mV peak-to-peak (see our previous report for more details 2 ).…”