title: Understanding the adsorption of CuPc and ZnPc on noble metal surfaces by combining quantum-mechanical modelling and photoelectron spectroscopy.
abstract: Phthalocyanines are an important class of organic semiconductors and, thus, their interfaces with metals are both of fundamental and practical relevance. In the present contribution we provide a combined theoretical and experimental study, in which we show that state-of-the-art quantum-mechanical simulations are nowadays capable of treating most properties of such interfaces in a quantitatively reliable manner. This is shown for Cu-phthalocyanine (CuPc) and Zn-phthalocyanine (ZnPc) on Au(111) and Ag(111) surfaces. Using a recently developed approach for efficiently treating van der Waals (vdW) interactions at metal/organic interfaces, we calculate adsorption geometries in excellent agreement with experiments. With these geometries available, we are then able to accurately describe the interfacial electronic structure arising from molecular adsorption. We find that bonding is dominated by vdW forces for all studied interfaces. Concomitantly, charge rearrangements on Au(111) are exclusively due to Pauli pushback. On Ag(111), we additionally observe charge transfer from the metal to one of the spin-channels associated with the lowest unoccupied π-states of the molecules. Comparing the interfacial density of states with our ultraviolet photoelectron spectroscopy (UPS) experiments, we find that the use of a hybrid functionals is necessary to obtain the correct order of the electronic states.
authors.affiliation: Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore. uenon@faculty.chiba-u.jp.
authors.forename: Yu Li
authors.initials: YL
authors.lastname: Huang
authors.affiliation: Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria. elisabeth.wruss@student.tugraz.at.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Wruss
authors.affiliation: Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria. david.egger@tugraz.at.
authors.forename: David A
authors.initials: DA
authors.lastname: Egger
authors.affiliation: Graduate School of Advanced Integration Science, Chiba University, 1- 33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan. kera@faculty.chiba-u.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kera
authors.affiliation: Graduate School of Advanced Integration Science, Chiba University, 1- 33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan. uenon@faculty.chiba-u.jp.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Ueno
authors.affiliation: Department of Chemical and Petroleum Engineering, University of Pittsburgh, 1249 Benedum Hall, Pittsburgh, PA 15261, USA. alsaidi@pitt.edu.
authors.forename: Wissam A
authors.initials: WA
authors.lastname: Saidi
authors.affiliation: Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynska Dolina, SK-84215 Bratislava, Slovakia. tomas.bucko@univie.ac.at.
authors.forename: Tomas
authors.initials: T
authors.lastname: Bucko
authors.affiliation: Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore. phyweets@nus.edu.sg.
authors.forename: Andrew T S
authors.initials: AT
authors.lastname: Wee
authors.affiliation: Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria. egbert.zojer@tugraz.at.
authors.forename: Egbert
authors.initials: E
authors.lastname: Zojer
mesh_terms: D000327:Adsorption; D003300:Copper / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D054833:Isoindoles; D008670:Metals / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D011789:Quantum Theory; D017967:Zinc Compounds
chemical_list: D007211:Indoles; D054833:Isoindoles; D008670:Metals; D009942:Organometallic Compounds; D017967:Zinc Compounds; C052159:Zn(II)-phthalocyanine; D003300:Copper; C013647:phthalocyanine