Comparison of Thin-Film Capacitor Geometries for the Detection of Volatile Organic Compounds Using a ZIF-8 Affinity Layer

Their chemical diversity, uniform pore sizes, and largeinternalsurface areas make metal-organic frameworks (MOFs) highly suitablefor volatile organic compound (VOC) adsorption. This work comparestwo geometries of capacitive VOC sensors that use the MOF materialZIF-8 as an affinity layer. When using a permeable top electrode (thickness< 25 nm), the metal-insulator-metal (MIM) sandwichconfiguration exhibits superior sensitivity, an improved detectionlimit, and a smaller footprint than the conventional interdigitatedelectrode layout. Moreover, the transduction of VOC adsorption inZIF-8 via MIM capacitors is more sensitive to polarVOCs and provides better selectivity at high loadings than gravimetricand optical transductions.