Formation of Metal–Organic Interface States
Upon deposition of a monolayer (ML) of 3,4,9,10-Perylenetetracarboxylic dianhydride (PTCDA) on top of Silver (111) (Ag(111)), the partially filled Shockley surface state disappears at its former energetically position and shifts up by 0.62 eV to become an unpopulated interface state (IS).
Left: normal emission single-color 2PPE spectra of PTCDA=Ag(111) for different coverage (top) and the clean surface (bottom). The clean surface (black) shows the image potential states, a signal originating from the sp-band and the Shockley-state. Upon adsorption of PTCDA, the Shockley state vanishes and the image potential states are damped. In addition a new state rises at 0.6 eV above EFermi (IS). Center: Map of the measured dispersion of the interface state (IS) for 1 ML (circles) and 2 ML (diamonds) of PTCDA together with the projected Ag(111) bulk bands (gray shaded area) and the Shockley state of the clean surface (dotted line). The effective mass at the gamma point (meff = 0.46 +- 0.1) is very close to the effective mass of the Shockley state (meff = 0.42 eV) and shows a lifetime of 54 fs at room temperature (right). The short lifetime indicates a high overlap of the IS wave function with the metal, which could be confirmed by DFT calculations.
The above figure displays a DFT-calculated wave function of 1,4,5,8-Naphthalenetetracarboxylic dianhydride on Silver (NTCDA/Ag(111)). IS probability density perpendicular to the surface, xy averaged over the unit cell. Inlay: Spatial distribution of the IS probability density at the gamma-point in the vicinity of the molecular plane.
The formation of interface states was observed for a variety of combinations between organic semiconductors and metal substrates. Their energetic position and lifetime show a systematic dependence on the bonding distance.
contact: Dr. Klaus Stallberg, Dr. Robert Wallauer, Prof. Dr. Ulrich Höfer
- R. Wallauer, M. Raths, K. Stallberg, L. Münster, D. Brandstetter, X. Yang, J. Güdde, P. Puschnig, S. Soubatch, C. Kumpf, F.C. Bocquet, F.S. Tautz, U. Höfer
Tracing orbital images on ultrafast time scales
Science 371, 1056 (2021), – First Release
- M. Marks, N. Armbrust, J. Güdde, and U. Höfer
Impact of Interface-State Formation on the Charge-Carrier Dynamics at Organic-Metal Interfaces
New J. Phys. 22, 093042 (2020).
- K. Stallberg, M. Shibuta, and U. Höfer
Temperature effects on the formation and the relaxation dynamics of metal-organic interface states
Phys. Rev. B 102, 121401(R) (2020).
- K. Stallberg, A. Namgalies, and U. Höfer
Photoluminescence Study of the Exciton Dynamics at PTCDA/Noble-Metal Interfaces
Phys. Rev. B 99, 125410 (2019).
- A. Lerch, J. E. Zimmermann, A. Namgalies, K. Stallberg, and U. Höfer
2PPE spectroscopy of unoccupied electronic states at CuPc/PTCDA/Ag(111) interfaces
J. Phys.-Condens. Mat., Special issue on internal interfaces 30, 494001 (2018).
- A. Lerch, L. Fernandez, M. Ilyn, M. Gastaldo, M. Paradinas, M. A. Valbuena, A. Mugarza, A. B. M. Ibrahim, J. Sundermeyer, U. Höfer, and F. Schiller
Electronic Structure of Titanylphthalocyanine Layers on Ag(111)
J. Phys. Chem. C 121, 25353 (2017).
- N. Armbrust, F. Schiller, J. Güdde, and U. Höfer
Model potential for the description of metal/organic interface states
Sci. Rep. 7, 46561 (2017).
- P. Jakob, N. L. Zaitsev, A. Namgalies, R. Tonner, I. A. Nechaev, F. S. Tautz, U. Höfer, and D. Sánchez-Portal
Adsorption geometry and the interface states: Relaxed and compressed phases of NTCDA/Ag(111)
Phys. Rev. B 94, 125436 (2016).
- N. L. Zaitsev, I. A. Nechaev, U. Höfer, and E. V. Chulkov
Adsorption geometry and electronic properties of flat-lying monolayers of tetracene on the Ag(111) surface
Phys. Rev. B 94, 155452 (2016).
- S. S. Tsirkin, N. L. Zaitsev, I. A. Nechaev, R. Tonner, U. Höfer, and E. V. Chulkov
Inelastic decay of electrons in Shockley-type metal-organic interface states
Phys. Rev. B 92, 235434 (2015).
- M. Marks, A. Schöll, and U. Höfer
Formation of metal-organic interface states studied with 2PPE
J. Electr. Spectrosc. 195, 263 (2014).
- M. C. E. Galbraith, M. Marks, R. Tonner, and U. Höfer
Formation of an organic/metal interface state from a Shockley resonance
J. Phys. Chem. Lett. 5, 50 (2014).
- M. Marks, C. H. Schwalb, S. Sachs, A. Schöll, and U. Höfer
Electronic structure and excited state dynamics in optically excited PTCDA films investigated with 2-photon photoemission
J. Chem. Phys. 139, 124701 (2013).
- M. Marks, C. Schmidt, C. H. Schwalb, T. Breuer, G. Witte, and U. Höfer
Temperature Dependent Structural Phase Transition at the Perfluoropentacene/Ag(111) Interface
J. Phys. Chem. C 116, 1904 (2012).
- M. Marks, N. L. Zaitsev, B. Schmidt, C. H. Schwalb, A. Schöll, I. A. Nechaev, P. M. Echenique, E. V. Chulkov and U. Höfer
Energy shift and wave function overlap of metal-organic interface states
Phys. Rev. B 84, 081301 (2011).
- C. H. Schwalb, M. Marks, A. Schöll, F. Reinert, E. Umbach, and U. Höfer
Time-resolved measurements of electron transfer processes at the PTCDA/Ag(111) interface
European Physical Journal B 75, 23 (2010).
- S. Sachs, C. H. Schwalb, M. Marks, A. Schöll, F. Reinert, E. Umbach and U. Höfer
Electronic structure at the perylene-tetracarboxylic acid dianhydride/Ag(111) interface studied with two-photon photoelectron spectroscopy
J. Chem. Phys. 131, 144701 (2009).
- C. H. Schwalb, S. Sachs, M. Marks, A. Schöll, F. Reinert, E. Umbach, and U. Höfer
Electron lifetimes in a Shockley-type metal-organic interface state
Phys. Rev. Lett. 101, 146801 (2008).