Surface‐Modified Phthalocyanine‐Based Two‐Dimensional Conjugated Metal–Organic Framework Films for Polarity‐Selective Chemiresistive Sensing
Mingchao Wang, Zhe Zhang, Haixia Zhong, Xing Huang, Wei Li, Mike Hambsch, Panpan Zhang, Zhiyong Wang, Petko St. Petkov, Thomas Heine, Stefan C. B. Mannsfeld, Xinliang Feng, Renhao Dong⧫
Abstract
Abstract 2D conjugated metal–organic frameworks (2D c ‐MOFs) are emerging as electroactive materials for chemiresistive sensors, but selective sensing with fast response/recovery is a challenge. Phthalocyanine‐based Ni 2 [MPc(NH) 8 ] 2D c ‐MOF films are presented as active layers for polarity‐selective chemiresisitors toward water and volatile organic compounds (VOCs). Surface‐hydrophobic modification by grafting aliphatic alkyl chains on 2D c ‐MOF films decreases diffused analytes into the MOF backbone, resulting in a considerably accelerated recovery progress (from ca. 50 to ca. 10 s) during humidity sensing. Toward VOCs, the sensors deliver a polarity‐selective response among alcohols but no signal for low‐polarity aprotic hydrocarbons. The octadecyltrimethoxysilane‐modified Ni 2 [MPc(NH) 8 ] based sensor displays high‐performance methanol sensing with fast response (36 s)/recovery (13 s) and a detection limit as low as 10 ppm, surpassing reported room‐temperature chemiresistors.