Transistor‐Based Work‐Function Measurement of Metal–Organic Frameworks for Ultra‐Low‐Power, Rationally Designed Chemical Sensors

Abstract

Ac lassic challenge in chemical sensingi ss electivity.M etal-organic frameworks (MOFs) are an exciting class of materials because they can be tuned for selective chemical adsorption. Adsorptione ventst riggerw ork-function shifts, which can be detectedw ith ac hemical-sensitive field-effect transistor (power % microwatts). In this work, several case studiesw ere used towards generalizing the sensing mechanism, ultimately towards our metal-centric hypothesis. HKUST-1 was used as ap roof-of-principle humidity sensor.The response is thickness independent, meaning the response is surfacel ocalized. ZIF-8 is demonstrated to be an NO 2 -sensing material,a nd the response is dominated by adsorptiona tm etal sites. Finally, MFM-300(In) shows how standard hard-soft acid-base theory can be used to qualitatively predict sensorr esponses. This paper sets the groundwork for using the tunability of metal-organic frameworks for chemicalsensing with distributed, scalable devices.[a] D.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.

The Role of Metal–Organic Frameworks in Electronic Sensors

“…addition, some MOFs with different metal ions (Mg,Co, Zn, Ni)w ere investigated as sensing materials in work-function devices. [54a,d,e] Recently,Gardner et al [76] also reported several MOF-based chemical-sensitive FET sensors,i ncluding HKUST-1, ZIF-8, and MFM-300 (In) (Figure 9a,b).…”

“…Reproducedw ith permission. [76] Copyright 2019 Wiley-VCH Verlag GmbH & Co.K GaA, Weinheim.c )Schematic representation of Kelvin probe configuration. The MOF film is deposited on the stationary electrode which is electricallyc onnected to the oscillating reference electrode.…”

The Role of Metal–Organic Frameworks in Electronic Sensors

“…In addition, some MOFs with different metal ions (Mg, Co, Zn, Ni) were investigated as sensing materials in work‐function devices [54a,d,e] . Recently, Gardner et al [76] . also reported several MOF‐based chemical‐sensitive FET sensors, including HKUST‐1, ZIF‐8, and MFM‐300 (In) (Figure 9 a,b).…”

“…b) Sensing mechanism: [79] when the sensing material adsorbs gas, the work function changes, inducing changes of the band bending of the underlying silicon. Reproduced with permission [76] . Copyright 2019 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim.…”

Reversible Protonation of Porphyrinic Metal‐Organic Frameworks Embedded in Nanoporous Polydimethylsiloxane for Colorimetric Sensing

“…harvesting, [7] water purification, [8] chemical sensing, [9] and others. Numerous organic molecules have been employed as primary building blocks for the development of unprecedented MOFs, some of them with the capability to be post-synthetically modified.…”