Semiconducting MOFs on ultraviolet laser-induced graphene with a hierarchical pore architecture for NO 2 monitoring.

Due to rapid urbanization worldwide, monitoring the concentration of nitrogen dioxide (NO 2 ), which causes cardiovascular and respiratory diseases, has attracted considerable attention. Developing real-time sensors to detect parts-per-billion (ppb)-level NO 2 remains challenging due to limited sensitivity, response, and recovery characteristics. Herein, we report a hybrid structure of Cu 3 HHTP 2 , 2D semiconducting metal-organic frameworks (MOFs), and laser-induced graphene (LIG) for high-performance NO 2 sensing. The unique hierarchical pore architecture of LIG@Cu 3 HHTP 2 promotes mass transport of gas molecules and takes full advantage of the large surface area and porosity of MOFs, enabling highly rapid and sensitive responses to NO 2 . Consequently, LIG@Cu 3 HHTP 2 shows one of the fastest responses and lowest limit of detection at room temperature compared with state-of-the-art NO 2 sensors. Additionally, by employing LIG as a growth platform, flexibility and patterning strategies are achieved, which are the main challenges for MOF-based electronic devices. These results provide key insight into applying MOFtronics as high-performance healthcare devices.