SKM 2023 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 26: Electrical, Dielectrical and Optical Properties of Thin Films

CPP 26.3: Talk

Tuesday, March 28, 2023, 14:30–14:45, MER 02

Programmed Assembly of Dipolar Precursors into Porous, Crystalline Molecular Thin Films — •Alexei Nefedov¹, Ritesh Haldar¹, Zhiyun Xu¹, Hannes Kühner¹, Dennis Hofmann², David Goll², Benedikt Sapotta¹, Stefan Hecht³, Marjan Krstić¹, Carsten Rockstuhl¹, Wolfgang Wenzel¹, Stefan Bräse¹, Petra Tegerer², Egbert Zojer⁴, and Christof Wöll¹ — ¹Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany — ²Universität Heidelberg, Heidelberg, Germany — ³RWTH Aachen University, Aachen, Germany — ⁴Graz University of Technology, Graz, Austria

Liquid-phase, quasi-epitaxial growth has been used to stack asymmetric, dipolar organic compounds on inorganic substrates, permitting porous, crystalline molecular materials which lack inversion symmetry. This allows material fabrication with built-in electric fields. We describe a new programmed assembly strategy based on metal-organic frameworks (MOFs) that facilitates crystalline, non-centrosymmetric space groups for achiral compounds. Electric fields are integrated into crystalline, porous thin films with an orientation normal to the substrate. Changes in electrostatic potential are detected via core-level shifts of marker atoms on the MOF thin films and agree with theoretical results. The integration of built-in electric fields into molecular solids creates possibilities for band structure engineering to control the alignment of electronic levels in organic molecules and it may also be used to tune the transfer of charges from donors loaded via programmed assembly into MOF pores.