TY  - JOUR
AU  - Baby, Anu
AU  - Gruenewald, Marco
AU  - Zwick, Christian
AU  - Otto, Felix
AU  - Forker, Roman
AU  - van Straaten, Gerben
AU  - Franke, Markus
AU  - Stadtmüller, Benjamin
AU  - Kumpf, Christian
AU  - Brivio, Gian Paolo
AU  - Fratesi, Guido
AU  - Fritz, Torsten
AU  - Zojer, Egbert
TI  - Fully Atomistic Understanding of the Electronic and Optical Properties of a Prototypical Doped Charge-Transfer Interface
JO  - ACS nano
VL  - 11
IS  - 10
SN  - 1936-086X
CY  - Washington, DC
PB  - Soc.
M1  - FZJ-2019-02538
SP  - 10495 - 10508
PY  - 2017
AB  - The current study generates profound atomistic insights into doping-induced changes of the optical and electronic properties of the prototypical PTCDA/Ag(111) interface. For doping K atoms are used, as KxPTCDA/Ag(111) has the distinct advantage of forming well-defined stoichiometric phases. To arrive at a conclusive, unambiguous, and fully atomistic understanding of the interface properties, we combine state-of-the-art density-functional theory calculations with optical differential reflectance data, photoelectron spectra, and X-ray standing wave measurements. In combination with the full structural characterization of the KxPTCDA/Ag(111) interface by low-energy electron diffraction and scanning tunneling microscopy experiments (ACS Nano 2016, 10, 2365–2374), the present comprehensive study provides access to a fully characterized reference system for a well-defined metal–organic interface in the presence of dopant atoms, which can serve as an ideal benchmark for future research and applications. The combination of the employed complementary techniques allows us to understand the peculiarities of the optical spectra of K2PTCDA/Ag(111) and their counterintuitive similarity to those of neutral PTCDA layers. They also clearly describe the transition from a metallic character of the (pristine) adsorbed PTCDA layer on Ag(111) to a semiconducting state upon doping, which is the opposite of the effect (degenerate) doping usually has on semiconducting materials. All experimental and theoretical efforts also unanimously reveal a reduced electronic coupling between the adsorbate and the substrate, which goes hand in hand with an increasing adsorption distance of the PTCDA molecules caused by a bending of their carboxylic oxygens away from the substrate and toward the potassium atoms.
LB  - PUB:(DE-HGF)16
C6  - pmid:28902494
UR  - <Go to ISI:>//WOS:000413992800097
DO  - DOI:10.1021/acsnano.7b05828
UR  - https://juser.fz-juelich.de/record/862190
ER  -