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.