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Electrostatic design of polar metal–organic framework thin films

Nascimbeni, Giulia; Wöll, Christof; Zojer, Egbert

Abstract:
In recent years, optical and electronic properties of metal–organic frameworks (MOFs) have increasingly shifted into the focus of interest of the scientific community. Here, we discuss a strategy for conveniently tuning these properties through electrostatic design. More specifically, based on quantum-mechanical simulations, we suggest an approach for creating a gradient of the electrostatic potential within a MOF thin film, exploiting collective electrostatic effects. With a suitable orientation of polar apical linkers, the resulting non-centrosymmetric packing results in an energy staircase of the frontier electronic states reminiscent of the situation in a pin-photodiode. The observed one dimensional gradient of the electrostatic potential causes a closure of the global energy gap and also shifts core-level energies by an amount equaling the size of the original band gap. The realization of such assemblies could be based on so-called pillared layer MOFs fabricated in an oriented fashion on a solid substrate employing layer by layer growth techniques. In this context, the simulations provide guidelines regarding the design of the polar apical linker molecules that would allow the realization of MOF thin films with the (vast majority of the) molecular dipole moments pointing in the same direction.

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Verlagsausgabe §
DOI: 10.5445/IR/1000128363
Veröffentlicht am 12.01.2021
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Funktionelle Grenzflächen (IFG)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 2079-4991
KITopen-ID: 1000128363
HGF-Programm 47.02.06 (POF III, LK 01) Zellpopul.auf Biofunk.Oberflächen IFG
Erschienen in Nanomaterials
Verlag MDPI
Band 10
Heft 12
Seiten Art.-Nr.: 2420
Schlagwörter metal–organic frameworks; electronic structure; electrostatic design; density functional theory; work-function change; polar MOFs; bonding asymmetry
Nachgewiesen in Scopus
Web of Science
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