Park Chungseong, Woo Junhee, Jeon Mingyu, Baek Jong Won, Shin Euichul, Kim Jihan, Park Steve, Kim Il-Doo
Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
ACS Nano. 2025 Mar 25;19(11):11230-11240. doi: 10.1021/acsnano.4c18848. Epub 2025 Mar 13.
Metal-organic frameworks (MOFs) are ideal for gas sensing due to their high porosity and chemical diversity. However, their low electrical conductivity has traditionally limited their application in chemiresistive-type sensors. The recent development of electrically conductive MOFs (cMOFs) has addressed this limitation. However, directly designing cMOFs with specific sensing properties remains challenging due to the limited understanding of their structure-property relationships. At this stage, the synergistic integration of cMOFs with conventional insulating MOFs has emerged as a viable solution, enabling diverse gas interactions and the rational design of sensing properties. Despite this potential, exploration of the diverse roles of MOFs in such composites remains underutilized. Herein, we develop a series of MOF-on-cMOF sensors and demonstrate their tunable sensing properties. A two-step solution-shearing-based film fabrication method enables facile integration of cMOFs with a wide range of conventional MOFs in layered structures. On cMOF thin film as a primary sensing layer, secondary MOF layers with different pore structures and adsorption properties were strategically selected and deposited. These layered film sensors exhibited tunable sensing properties, including enhanced sensitivity, selectivity, response speed, and recovery for analytes such as NH, HS, and NO. These improvements cannot be achieved solely through the conventional role of MOFs as sieving layers. Furthermore, computational analyses elucidated the structure-property relationships underlying these improvements, offering key insights into the rational design of MOF-based gas sensors.
金属有机框架材料（MOFs）因其高孔隙率和化学多样性而非常适合用于气体传感。然而，其低电导率传统上限制了它们在化学电阻型传感器中的应用。导电MOFs（cMOFs）的最新发展解决了这一限制。然而，由于对其结构-性能关系的理解有限，直接设计具有特定传感特性的cMOFs仍然具有挑战性。在现阶段，将cMOFs与传统绝缘MOFs进行协同整合已成为一种可行的解决方案，能够实现多种气体相互作用并合理设计传感特性。尽管有这种潜力，但MOFs在这类复合材料中的多种作用仍未得到充分探索。在此，我们开发了一系列基于cMOF的MOF传感器，并展示了它们可调节的传感特性。一种基于两步溶液剪切的薄膜制备方法能够轻松地将cMOFs与各种传统MOFs整合到分层结构中。在作为主要传感层的cMOF薄膜上，策略性地选择并沉积了具有不同孔结构和吸附特性的二级MOF层。这些分层薄膜传感器表现出可调节的传感特性，包括对NH₃、H₂S和NO等分析物的灵敏度提高、选择性增强、响应速度加快以及恢复性能改善。这些改进不能仅通过MOFs作为筛分层的传统作用来实现。此外，计算分析阐明了这些改进背后的结构-性能关系，为基于MOF的气体传感器的合理设计提供了关键见解。
