Welding Metallophthalocyanines into Bimetallic Molecular Meshes for Ultrasensitive, Low-Power Chemiresistive Detection of Gases

This paper describes the first demonstration of using a series of isoreticular nickel phthalocyanine- and nickel naphthalocyanine-based bimetallic conductive two-dimensional (2D) metal–organic frameworks (MOFs) as active materials in chemiresistive sensing of gases. Devices achieve exceptional sensitivity at sub-part-per-million (ppm) to part-per-billion (ppb) detection limits toward NH 3 (0.31–0.33 ppm), H 2 S (19–32 ppb), and NO (1.0–1.1 ppb) at low driving voltages (0.01–1.0 V) within 1.5 min of exposure. The devices maintain their performance in the presence of humidity (5000 ppm of H 2 O). The isoreticular analogs enable modular control over selectivity and sensitivity in gas sensing through different combinations of linkers and metal nodes. Electron paramagnetic resonance spectroscopy and X-ray photoelectron spectroscopy studies suggest that the chemiresistive response of the MOFs involves charge transfer interactions triggered by the analytes adsorbed on MOFs.