Self-assembly of a DPDI+PTCDA mixed layer on Ag(111): Theory and experiments
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We present a combined experimental and theoretical investigation of the self-assembly of a binary mixture of 4,9-diaminoperylene-quinone-3,10-diimine (DPDI) and 3,4,9,10-perylene-tetracarboxylic acid dianhydride (PTCDA) molecules on Ag(111). At a 1:1 ratio, the two molecules intermix to form a long-range ordered bimolecular network stabilized by intermolecular hydrogen bonding. We show, by means of low energy electron diffraction (LEED) measurements, that the self-assembled network is commensurate with the underlying silver surface. Scanning tunneling microscope (STM) measurements and density functional theory (DFT) calculations are combined to unravel the structural configuration of the system. Core-level binding energy shifts for the 1s levels of the O atoms, obtained from both X-ray photoelectron spectroscopy (XPS) measurements and DFT simulations, are reported and compared. Our DFT calculations allow the investigation of the interplay between molecule-molecule and molecule-surface interactions in the network. Our combined experimental-theoretical approach allows a precise characterization of the structural and electronic properties of the studied system.
IdentifiersURN: urn:nbn:se:liu:diva-117846OAI: oai:DiVA.org:liu-117846DiVA: diva2:811213