In this study, we examine charge transfer between graphene and molecular semiconductors, parahexaphenyl and C60. Through in-situ measurements of the current, we directly probe the charge transfer as the interfacial dipole is formed. We demonstrate that adsorbed molecules do not affect electron scattering rates in graphene. However, the molecules introduce p-type doping with only...
Recent applications of indigo as a functional building block for organic electronics have renewed the interest in the chemical and physical properties of this molecule. We report on its electronic structure for the isolated molecule as well as for the bulk molecular crystal phases. Further we investigate the optical properties of the bulk phases. For the molecule we employ an optimally tuned...
We have studied the growth of perfluoro-pentacene films on Ag(110) with photoelectron emission microscopy (PEEM) and differential (optical) reflectance spectroscopy (DRS). The setup allows recording PEEM images and DRS spectra simultaneously, providing the unique opportunity to correlate the morphology and electronic structure (PEEM) with the associated optical response (DRS). We will...
Cobalt-pyrphyrin (Co-Pyr) is a promising water reduction catalyst. Cu$_2$O(111) and TiO$_2$(110) with monolayer coverage of Co-Pyr were studied for pressures spanning from UHV up to 1mbar of water vapor. Under UV illumination, surface photovoltage shifts of ΔE$_k$=+120meV are observed on Cu$_2$O(111). X-ray absorption spectroscopy of the Co L3-edge was used to monitor the electronic structure...
Hematite is a promising material for electrochemical water splitting with a suitable bandgap, but it shows poor electrochemical performance.
We focus on the (012) surface. At ambient pressure a bulk terminated (1x1) surface termination exists which is converted into a (2x1) reconstruction at high temperature in UHV. Experimental data confirm the reconstruction.
We calculated the...
Transitions of individual molecules on surfaces are traditionally described with energy barriers and attempt rates using an Arrhenius law. This yields consistent energy barrier values, but the attempt rates are orders of magnitude below expected oscillation frequencies of particles in potential wells. Using LTSTM to measure an individual dibutylsulfide molecule on Au(111), we find that the...
Recent experimental observations in our laboratory reveal a striking enantioselectivity of the PdGa:A(111) surface with respect to adsorption of the prochiral molecule 9-ethynylphenanthrene.
The findings highlight the great potential of intrinsically chiral intermetallic compounds for the development of novel, enantioselective catalysts potentially applicable in realistic conditions.
Using...
