Two-Dimensional Chemiresistive Covalent Organic Framework with High Intrinsic Conductivity.

This paper describes the synthesis of a novel intrinsically conductive two-dimensional (2D) covalent organic framework (COF) through the aromatic annulation of 2,3,9,10,16,17,23,24-octa-aminophthalocyanine nickel(II) and pyrene-4,5,9,10-tetraone. The intrinsic bulk conductivity of the COF material (termed ) reached 2.51 × 10 S/m, and increased by 3 orders of magnitude with I doping. Electronic calculations revealed an anisotropic band structure, with the possibility for significant contribution from out-of-plane charge-transport to the intrinsic bulk conductivity. Upon integration into chemiresistive devices, this conductive COF showed excellent responses to various reducing and oxidizing gases, including NH, HS, NO, and NO, with parts-per-billion (ppb) limits of detection (for NH = 70 ppb, for HS = 204 ppb, for NO = 5 ppb, and for NO = 16 ppb based on 1.5 min exposure). Electron paramagnetic resonance spectroscopy and X-ray photoelectron spectroscopy studies suggested that the chemiresistive response of the involves charge transfer interactions between the analyte and nickelphthalocyanine component of the framework.