Solvent-controlled ion-coupled charge transport in microporous metal chalcogenides

McKenzie, Jacob; Kempler, Paul A.; Brozek, Carl K.

doi:10.1039/d2sc05090k

Cited by 2 publications

(1 citation statement)

References 90 publications

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“…S8). Subsequently, and in analogy to literature precedence, 22,[39][40][41] electrochemical impedance spectroscopy (EIS) was used to probe the respective redox conductivities (details can be found in the Methods section). This AC voltammetry technique applies a small voltage perturbation over a wide range of frequencies, differentiating physical processes happening at distinct time scales.…”

Section: Redox State Dependent Conductivity and Semiconductor/insulat...mentioning

confidence: 99%

Experimental Manifestation of Redox-Conductivity in Metal-Organic Frameworks and its Implication for Semiconductor/Insulator Switching

Kumar

Johnson

et al. 2023

Preprint

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Electrical conductivity through metal-organic frameworks (MOFs) is almost exclusively interpreted in terms of band theory. This common practice neglects the fact that MOFs with electronically isolated redox active units will in fact show redox conductivity. Herein, we demonstrate unambiguous experimental evidence for redox conductivity in a MOF for the first time. The study was conducted on FTO-grown thin films of Zn(pyrazol-NDI) (pyrazol-NDI = 1,4-bis[(3,5-dimethyl)-pyrazol-4-yl]naphthalenediimide). Following Nernstian behavior, the proportion of reduced and oxidized NDI linkers can be adjusted by the applied potential. Through a series of conductivity measurements, it is demonstrated that the MOF exhibits minimal electric resistance at the mid-point potentials of the NDI linker, and conductivity is enhanced by more than 10000-fold compared to that of either the neutral or completely reduced films. The generality of redox conductivity is demonstrated in different MOFs, and its implication for applications that require switching between insulating and semiconducting regimes is discussed.

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Section: Redox State Dependent Conductivity and Semiconductor/insulat...mentioning

confidence: 99%

Experimental Manifestation of Redox-Conductivity in Metal-Organic Frameworks and its Implication for Semiconductor/Insulator Switching

Kumar

Johnson

et al. 2023

Preprint

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Experimental manifestation of redox-conductivity in metal-organic frameworks and its implication for semiconductor/insulator switching

Kumar

Johnson

et al. 2023

Nat Commun

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Electric conductivity in metal-organic frameworks (MOFs) follows either a band-like or a redox-hopping charge transport mechanism. While conductivity by the band-like mechanism is theoretically and experimentally well established, the field has struggled to experimentally demonstrate redox conductivity that is promoted by the electron hopping mechanism. Such redox conductivity is predicted to maximize at the mid-point potential of the redox-active units in the MOF, and decline rapidly when deviating from this situation. Herein, we present direct experimental evidence for redox conductivity in fluorine-doped tin oxide surface-grown thin films of Zn(pyrazol-NDI) (pyrazol-NDI = 1,4-bis[(3,5-dimethyl)-pyrazol-4-yl]naphthalenediimide). Following Nernstian behavior, the proportion of reduced and oxidized NDI linkers can be adjusted by the applied potential. Through a series of conductivity measurements, it is demonstrated that the MOF exhibits minimal electric resistance at the mid-point potentials of the NDI linker, and conductivity is enhanced by more than 10000-fold compared to that of either the neutral or completely reduced films. The generality of redox conductivity is demonstrated in MOFs with different linkers and secondary building units, and its implication for applications that require switching between insulating and semiconducting regimes is discussed.

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Solvent-controlled ion-coupled charge transport in microporous metal chalcogenides

Abstract: Interactions between ions and itinerant charges govern electronic processes ranging from the redox chemistry of molecules to the conductivity of organic semiconductors, but remain an open frontier in the study of microporous materials.

Cited by 2 publications

References 90 publications

Experimental Manifestation of Redox-Conductivity in Metal-Organic Frameworks and its Implication for Semiconductor/Insulator Switching

Experimental Manifestation of Redox-Conductivity in Metal-Organic Frameworks and its Implication for Semiconductor/Insulator Switching

Experimental manifestation of redox-conductivity in metal-organic frameworks and its implication for semiconductor/insulator switching

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