title: Electric transport properties of surface-anchored metal-organic frameworks and the effect of ferrocene loading.
abstract: Understanding of the electric transport through surface-anchored metal-organic frameworks (SURMOFs) is important both from a fundamental perspective as well as with regards to possible future applications in electronic devices. To address this mostly unexplored subject, we integrated a series of representative SURMOF thin films, formed by copper nodes and trimesic acid and known as HKUST-1, in a mercury-drop-based tunneling junction. Although the transport properties of these SURMOFs are analogous to those of hybrid metal-organic molecular wires, manifested by a very low value of the tunneling decay constant (β ≈ 0.006 Å(-1)), they are at the same time found to be consistent with a linear increase of resistance with film thickness. Upon loading of SURMOF pores with ferrocene (Fc), a noticeable increase in transport current was observed. A transport model and ab initio electronic structure calculations were used to reveal a hopping transport mechanism and to relate the changes upon Fc loading to those of the electronic and vibrational structures of the SURMOF films.
authors: †Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany.
authors: Jianxi
authors: J
authors: Liu
authors: ‡Applied Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany.
authors: Tobias
authors: T
authors: Wächter
authors: §Department of Physics, University of Konstanz, 78457 Konstanz, Germany.
authors: Andreas
authors: A
authors: Irmler
authors: †Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany.
authors: Peter G
authors: PG
authors: Weidler
authors: †Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany.
authors: Hartmut
authors: H
authors: Gliemann
authors: §Department of Physics, University of Konstanz, 78457 Konstanz, Germany.
authors: Fabian
authors: F
authors: Pauly
authors: †Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany.
authors: Veronica
authors: V
authors: Mugnaini
authors: ‡Applied Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany.
authors: Michael
authors: M
authors: Zharnikov
authors: †Institute of Functional Interfaces (IFG), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany.
authors: Christof
authors: C
authors: Wöll
keywords: conduction mechanism; density functional theory; electric transport properties; mercury-based tunneling junctions; surface-anchored metal−organic frameworks