Metal–organic frameworks (MOFs) are hybrid materials based on crystalline coordination polymers that consist of metal ions connected by organic ligands. In addition to the traditional applications in gas storage and separation or catalysis, the long-range crystalline order in MOFs, as well as the tunable coupling between the organic and inorganic constituents, has led to the recent development of electrically conductive MOFs as a new generation of electronic materials. However, to date, the nature of charge transport in the MOFs has remained elusive. Here we demonstrate, using high-frequency terahertz photoconductivity and Hall effect measurements, Drude-type band-like transport in a semiconducting, π–d conjugated porous Fe 3 (THT) 2 (NH 4 ) 3 (THT, 2,3,6,7,10,11-triphenylenehexathiol) two-dimensional MOF, with a room-temperature mobility up to ~ 220 cm 2 V –1 s –1 . The temperature-dependent conductivity reveals that this mobility represents a lower limit for the material, as mobility is limited by impurity scattering. These results illustrate the potential for high-mobility semiconducting MOFs as active materials in thin-film optoelectronic devices.
Bibliographical noteFunding Information:
This work was financially supported by the ERC Grant on 2DMATER, HIPER-G and EU Graphene Flagship, European Science Foundation (ESF), Coordination Networks: Building Blocks for Functional Systems (SPP 1928, COORNET) and the German Science Council. Financial support by the Max Planck Society is also acknowledged. We acknowledge the CFAED (Center for Advancing Electronics Dresden). E.C. acknowledges financial support from the Max Planck Graduate Center and the Regional Government of Comunidad de Madrid under project 2017-T1/AMB-5207. R.D. gratefully appreciates funding from the Alexander von Humboldt-Foundation. H.A. and A.E. are grateful to the Initiative and Networking Fund of the Helmholtz Association of German Research Centers through the International Helmholtz Research School for Nanoelectronic Networks, IHRS NANONET (VH-KO-606). We appreciate LPKF Laser & Electronics for the fabrication of the Hall bar geometry by laser ablation. We acknowledge the Dresden Center for Nanoanalysis (DCN) at TUD and P. Formanek (Leibniz Institute for Polymer Research, IPF, Dresden) for the use of facilities, and we appreciate X. Zhang, T. Zhang, F. Ortmann and K. S. Schellhammer for the helpful discussion. P.P. and T.H. thank ZIH Dresden for providing high-performance computing facilities.
© 2018, The Author(s), under exclusive licence to Springer Nature Limited.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering