Hybridization of Organic Molecules with Metal Substrates in the Presence of Surface Passivation Layers

• Applicants: Professor Dr. Torsten Fritz; Professor Dr. Jörg Kröger
• Subject Area: Experimental Condensed Matter Physics ; Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: from 2017 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 327143884

• Final Report Year: 2021

Final Report Abstract

The Ilmenau group used low-temperature scanning tunneling microscopy and spectroscopy to explore the efficiency of graphene, hexagonal boron nitride and NaCl in reducing the hybridization of molecular orbitals from the metal substrate. All mentioned materials represent – expectedly – suitable buffer layers. This result is based on the occurrence of lattice phonons, Landau levels in external magnetic fields, pronounced vibronic progression and single-molecule fluorescence. Several unexpected results were obtained, too. Although generally considered as similarly appropriate decoupling layers the two-dimensional materials graphene and hexagonal boron nitride behave markedly differently, irrespective of the metal surface they are adsorbed to. Vibronic resonances occur with sharp spectral linewidths, up to a high vibrational quantum number and, moreover, exhibit progression of vibronic progression with two involved molecular vibrational quanta on hexagonal boron nitride; on graphene, in contrast, vibronic progression is weakly developed with broad resonances. This surprising behavior is traced to the widely gapped electronic structure of hexagonal boron nitride opposed to the semi-metal character of graphene. A general conclusion of the research activities funded in this project is the efficient reduction of the orbital-selective hybridization with the metal substrate if the orbital energies fall well into the (wide) band gap of the decoupling layer. The smaller the interaction of the buffer layer with the metal surface is, the more efficient is the suppression of the residual molecule-metal hybridization.

Publications

• "Influence of Film and Substrate Structure on Photoelectron Momentum Maps of Coronene Thin Films on Ag(111)", J. Phys. Chem. C 121, 12285–12293 (2017)
  C. Udhardt, F. Otto, C. Kern, D. Lüftner, T. Huempfner, T. Kirchhuebel, F. Sojka, M. Meissner, B. Schröter, R. Forker, P. Puschnig, and T. Fritz
  
• "Ordered Superstructures of a Molecular Electron Donor on Au(111)", Langmuir 33, 6978–6984 (2017)
  A. Mehler, T. Kirchhuebel, N. Néel, F. Sojka, R. Forker, T. Fritz, and J. Kröger
  
• "Ordered Growth and Electronic Properties of 1,2:8,9-Dibenzopentacene (trans-DBPen) on Ag(111)", J. Phys. Chem. C 122, 8348–8355 (2018)
  F. Otto, T. Huempfner, M. Schaal, C. Udhardt, L. Vorbrink, B. Schroeter, R. Forker, and T. Fritz
  
• "The Evolution of Intermolecular Energy Bands of Occupied and Unoccupied Molecular States in Organic Thin Films", J. Phys. Chem. C 122, 12090–12097 (2018)
  Y. Kashimoto, K. Yonezawa, M. Meissner, M. Gruenewald, T. Ueba, S. Kera, R. Forker, T. Fritz, and H. Yoshida
  
• "Fraternal twins: distinction between PbPc and SnPc by their switching behavior in a scanning tunnelling microscope", J. Phys.: Condens. Matter 31, 134004 (2019)
  R. Forker, M. Gruenewald, F. Sojka, J. Peuker, P. Mueller, C. Zwick, T. Huempfner, M. Meissner, and T. Fritz
  
• "The role of initial and final states in molecular spectroscopies", Phys. Chem. Chem. Phys. 21, 12730–12747 (2019)
  T. Kirchhuebel, O. L. A. Monti, T. Munakata, S. Kera, R. Forker, and T. Fritz
  
• “Role of Initial and Final States in Molecular Spectroscopies: Example of Tetraphenyldibenzoperiflanthene (DBP) on Graphite”, J. Phys. Chem. C 124, 19622–19638 (2020)
  T. Kirchhuebel, S. Kera, T. Munakata, N. Ueno, R. Shiraishi, T. Yamaguchi, K. Yonezawa, T. Ueba, F. Bussolotti, J. Yang, T. Yamada, R. Mori, S. Kunieda, T. Huempfner, M. Gruenewald, R. Forker, and T. Fritz
  
• „High Potassium Concentrations Nested in Epitaxial Monolayers of a Flexible Lander-Type Molecule on Ag(111)“, J. Phys. Chem. C 124, 4114–4127 (2020)
  F. Otto, T. Kirchhuebel, A. Baby, F. Sojka, G. Fratesi, T. Fritz, and R. Forker
  
• „Hybridization vs decoupling: influence of an h-BN interlayer on the physical properties of a lander-type molecule on Ni(111)“, Beilstein J. Nanotechnol. 11, 1168–1177 (2020)
  M. Schaal, T. Aihara, M. Gruenewald, F. Otto, J. Domke, R. Forker, H. Yoshida, and T. Fritz
  
• “Recent Progress in the Consistent Interpretation of Complementary Spectroscopic Results Obtained on Molecular Systems”, Adv. Optical Mater. 9, 2100200 (2021)
  R. Forker, M. Gruenewald, T. Kirchhuebel, and T. Fritz