Fig. 4

The geometry of the molecular SET environment of indigo (a) or Tyrian purple (b). Both molecules are modeled within an electrostatic environment, which simulates metal source-drain electrodes on top of a dielectric substrate (shellac) with a metal back-gate. ΔV_H is denoted for the Hartree potential difference calculated by solving the Poisson equation. The contour plot shows the induced electrostatic potential for a V _G value of 2 V and zero source-drain bias. The molecular geometries were obtained by relaxing the molecules in the neutral state