Kinetic Trapping of Charge-Transfer Molecules at Metal Interfaces.

Despite the common expectation that conjugated organic molecules on metals adsorb in a flat-lying layer, several recent studies have found coverage-dependent transitions to upright-standing phases, which exhibit notably different physical properties. In this work, we argue that from an energetic perspective, thermodynamically stable upright-standing phases may be more common than hitherto thought. However, for kinetic reasons, this phase may often not be observed experimentally.

Interplay of Adsorption Geometry and Work Function Evolution at the TCNE/Cu(111) Interface.

The adsorption of organic electron acceptors on metal surfaces is a powerful way to change the effective work function of the substrate through the formation of charge-transfer-induced dipoles. The work function of the interfaces is hence controlled by the redistribution of charges upon adsorption of the organic layer, which depends not only on the electron affinity of the organic material but also on the adsorption geometry. As shown in this work, the latter dependence controls the work function also in the case of adsorbate layers exhibiting a mixture of various adsorption geometries.

Orientation, electronic decoupling and band dispersion of heptacene on modified and nanopatterned copper surfaces.

The adsorption of heptacene (7 A) on Cu(110) and Cu(110)-(2 × 1)-O was studied with scanning tunneling microscopy, photoemission orbital tomography and density functional calculations to reveal the influence of surface passivation on the molecular geometry and electronic states. We found that the charge transfer into the 7 A molecules on Cu(110) is completely suppressed for the oxygen-modified Cu surface. The molecules are aligned along the Cu-O rows and uncharged.

Impact of Iodine Electrodeposition on Nanoporous Carbon Electrode Determined by EQCM, XPS and In Situ Raman Spectroscopy.

The charging of nanoporous carbon via electrodeposition of solid iodine from iodide-based electrolyte is an efficient and ecofriendly method to produce battery cathodes. Here, the interactions at the carbon/iodine interface from first contact with the aqueous electrolyte to the electrochemical polarization conditions in a hybrid cell are investigated by a combination of in situ and ex situ methods. EQCM investigations confirm the flushing out of water from the pores during iodine formation at the positive electrode.