A Mono‐Boron Complex‐Based Fluorescent Nanofilm with Enhanced Sensing Performance for Methylamine in Vapor Phase

Abstract The performance of a film‐based fluorescent sensor is highly dependent on the innovative design of the sensing films aiming to elevate usability of sensing units, and enhance mass transfer of analytes within the fluorescent adlayer. Herein, a highly porous and uniform fluorescent nanofilm which is fabricated through an interfacially confined dynamic‐covalent reaction between benzene‐1,3,5‐tricarbo‐hydrazide and a mono‐boron complex of 8‐hydroxy‐quinoline is reported. Remarkably, the thicknesses of the nanofilms prepared in this way can be modulated from tens to hundreds of nanometers. In addition, the nanofilms demonstrate much improved photochemical stability. Sensing performance studies reveal that the nanofilm is super‐sensitive and selective to the presence of amines, especially methylamine (MA) in vapor phase. Specifically, the detection limit to MA is lower than 2.82 mg m⁻³, and the presence of the vapors of water, aromatic hydrocarbons, aliphatic hydrocarbons, alcohols, ketones, and other common organic compounds showed little effect upon the sensing. Moreover, the sensing is highly reversible. With the innovation in adlayer structure, substrate effect as commonly found in routine film‐based sensing is avoided, which must bring convenience for device making. In this work, different film‐based sensors are fabricated, suggesting their potential applications in various scenarios.