Figure 1: Cartoon of our approach.
(a) MBB-1 is formed by a linear alkyl tail (sketched as a grey rod) and a photoreactive diazirine head group (red square). The latter undergoes photolysis under exposure to ultraviolet light in chloroform (CHCl3) solution forming different reaction products in a mixture (MBB-2) with modified head groups (blue squares). Molecular self-assembly occurs by spin-coating a solution of MBB-1 or MBB-2 on graphene’s surface giving rise to supramolecular lattices with identical unit cell for MBB-1 and MBB-2. However, the head groups in MBB-1 and MBB-2 induce different gating effects, resulting in 1D periodic potentials with different amplitude (blue versus red) but with the same 1D periodicity. (b) Chemical structures of the molecules. The main reaction product obtained by ultraviolet irradiation in CHCl3 is shown in blue, while other products are listed in Supplementary Figs 1–3. (c) In situ monitoring of the photolysis through ultraviolet–visible spectroscopy (concentration of MBB-1: 2.2 × 10–3 M in CHCl3; path length: 2 mm (quartz cell); room temperature). In particular, absorption spectra of MBB-1 (red) and MBB-2 (blue) are shown before and after ultraviolet irradiation at λ=365 nm for 30 min.
