Figure 1

Side (a) and top (b) view of the SAM structure of $4^{\prime }\mathrm{\text{−}}X\mathrm{\text{−}}4$-mercaptobiphenyl on Au(111) where $X={\mathrm{NH}}_2$, SH, and CN. The $c(\surd 3\times 3)$ surface unit cell is indicated by the contour in (b).Reuse & Permissions

Figure 2

(a) Plane-averaged electrostatic potential (eV per elementary charge $q_{\mathrm{e}}$) of a 5-layer Au(111) slab (left). Also indicated is the metal Fermi energy $E_{\mathrm{F}}$, its work function ${\Phi }_{\mathrm{Au}(111)}$, the vacuum level $V_{\mathrm{vac}}$, and the molecular HOMO levels (horizontal lines, right) as well as the molecular ionization potentials ($IP$). (b) Plane-averaged electrostatic potential, left and right vacuum levels ($V_{\mathrm{vac}}^{\mathrm{left}}$, $V_{\mathrm{vac}}^{\mathrm{right}}$) and ionization potentials ($I{P}^{\mathrm{left}}$, $I{P}^{\mathrm{right}}$) of the hydrogen terminated molecular layers (right) compared to the isolated gold slab (left). (c) Potential of the SAMs adsorbed onto Au(111). The HOMO is located at $\Delta E$ below $E_{\mathrm{F}}$, ${\Phi }_{\mathrm{Au}(111)}$ is changed to ${\Phi }_{\mathrm{Au}}^{\mathrm{mod}}$, and $I{P}^{\mathrm{right}}$ to $I{P}_{\mathrm{SAM}}^{\mathrm{right}}$. The gray boxes indicate that the isolated molecules and the hydrogen terminated molecular layers have been calculated separately, in the absence of any gold.Reuse & Permissions

Figure 3

Plane-integrated charge density difference ${\rho }_{\mathrm{diff}}$ (a) in units of elementary charge $q_{\mathrm{e}}/\AA$ and the electrostatic potential drop BD (b) across the SAM/metal interface resulting from the difference between the S-H and S-Au bonding in eV per elementary charge $q_{\mathrm{e}}$. The vertical lines mark the positions of the gold, sulfur, and substitution ($X$) atoms.Reuse & Permissions