Formation of an Organic/Metal Interface State from a Shockley Resonance

• Published in: The journal of physical chemistry letters Vol. 5; no. 1; pp. 50 - 55
• Main Authors: Galbraith, Martin C. E, Marks, Manuel, Tonner, Ralf, Höfer, Ulrich
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 02.01.2014
• Subjects: Surfaces, Interfaces, Porous Materials, and Catalysis; electron dynamics; organic thin films; PTCDA; time-resolved 2-photon photoemission (2PPE); charge transfer; density functional theory
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/jz402249b

The emergence of an organic/metal interface state is studied for the interface between 3,4,9,10-perylene-tetracarboxylic acid dianhydride (PTCDA) and Ag(100) by means of time- and angle-resolved two-photon photoemission and density functional theory. The interface state is located in the projected band gap of Ag(100), 2.3 eV above the Fermi level, and has an electron lifetime in the 10 fs range. The interface state has no direct counterpart on the clean Ag(100) surface, which only exhibits a broad resonance at ≈1 eV lower energy. Our results thus show that organic overlayers are able to shift such a resonance substantially and even qualitatively change its character to a distinct electronic state at the interface.