Two-Dimensional Electrically Conductive Metal-Organic Frameworks as Chemiresistive Sensors

Metal-organic frameworks (MOFs) have emerged asattractivechemical sensing materials due to their exceptionally high porosityand chemical diversity. Nevertheless, the utilization of MOFs in chemiresistivetype sensors has been hindered by their inherent limitation in electricalconductivity. The recent emergence of two-dimensional conductive MOFs(2D c-MOFs) has addressed this limitation by offering enhanced electricalconductivity, while still retaining the advantageous properties ofMOFs. In particular, c-MOFs have shown promising advantages for thefabrication of sensors capable of operating at room temperature. Thus,active research on gas sensors utilizing c-MOFs is currently underway,focusing on enhancing sensitivity and selectivity. To comprehend thepotential of MOFs as chemiresistive sensors for future applications,it is crucial to understand not only the fundamental properties ofconductive MOFs but also the state-of-the-art works that contributeto improving their performance. This comprehensive review delves intothe distinctive characteristics of 2D c-MOFs as a new class of chemiresistors,providing in-depth insights into their unique sensing properties.Furthermore, we discuss the proposed sensing mechanisms associatedwith 2D c-MOFs and provide a concise summary of the strategies employedto enhance the sensing performance of 2D c-MOFs. These strategiesencompass a range of approaches, including the design of metal nodesand linkers, morphology control, and the synergistic use of compositematerials. In addition, the review thoroughly explores the prospectsof 2D c-MOFs as chemiresistors and elucidates their remarkable potentialfor further advancements. The insights presented in this review shedlight on future directions and offer valuable opportunities in thechemical sensing research field.