Triphenylene-Derived Electron Acceptors and Donors on Ag(111): Formation of Intermolecular Charge-Transfer Complexes with Common Unoccupied Molecular States

Kathrin Müller*, Nico Schmidt, Stefan Link, Rene Riedel, Julian Bock, Walter Malone, Karima Lasri, Abdelkader Kara, Ulrich Starke, Milan Kivala, Meike Stöhr

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Over the past years, ultrathin films consisting of electron donating and accepting molecules have attracted increasing attention due to their potential usage in optoelectronic devices. Key parameters for understanding and tuning their performance are intermolecular and molecule–substrate interactions. Here, the formation of a monolayer thick blend of triphenylene‐based organic donor and acceptor molecules from 2,3,6,7,10,11‐hexamethoxytriphenylene (HAT) and 1,4,5,8,9,12‐hexaazatriphenylenehexacarbonitrile (HATCN), respectively, on a silver (111) surface is reported. Scanning tunneling microscopy and spectroscopy, valence and core level photoelectron spectroscopy, as well as low‐energy electron diffraction measurements are used, complemented by density functional theory calculations, to investigate both the electronic and structural properties of the homomolecular as well as the intermixed layers. The donor molecules are weakly interacting with the Ag(111) surface, while the acceptor molecules show a strong interaction with the substrate leading to charge transfer and substantial buckling of the top silver layer and of the adsorbates. Upon mixing acceptor and donor molecules, strong hybridization occurs between the two different molecules leading to the emergence of a common unoccupied molecular orbital located at both the donor and acceptor molecules. The donor acceptor blend studied here is, therefore, a compelling candidate for organic electronics based on self‐assembled charge‐transfer complexes.
Original languageEnglish
Article number1901741
Number of pages10
JournalSmall
Volume15
Issue number33
Early online date2-Jul-2019
DOIs
Publication statusPublished - 16-Aug-2019

Keywords

  • ENERGY-LEVEL ALIGNMENT
  • TRANSITION-METAL SURFACES
  • LONG-RANGE INTERACTIONS
  • THIN-FILM TRANSISTORS
  • WORK-FUNCTION
  • ADSORPTION
  • FINGERPRINTS
  • OXIDATION
  • CHEMISTRY
  • BENZENE

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