Printed electronics promises the realization of low-cost electronic systems on flexible substrates over large areas. In order to achieve this, high quality patterns need to be printed at high speeds. Gravure printing is a particularly promising technique that is both scalable and offers micron-scale resolution. Here, we review the tremendous progress that has recently been made to push gravure printing beyond its traditional limitations in the graphic arts. Rolls with far greater precision than traditional rolls and with sub-5 μ m resolution can be fabricated utilizing techniques leveraging the precision of silicon microfabrication. Physical understanding of the sub-processes that constitute the gravure process is required to fully utilize the potential of gravure. We review the state-of-the-art of this understanding both for single cells and patterns of multiple cells to print high-resolution features as well as highly-uniform layers. Finally, we review recent progress on gravure printed transistors as an important technology driver. Fully high-speed printed transistors with sub-5 μ m channel length and sub-5 V operation can be printed with gravure.

Due to rapid urbanization worldwide, monitoring the concentration of nitrogen dioxide (NO₂), which causes cardiovascular and respiratory diseases, has attracted considerable attention. Developing real-time sensors to detect parts-per-billion (ppb)-level NO₂ remains challenging due to limited sensitivity, response, and recovery characteristics. Herein, we report a hybrid structure of Cu₃HHTP₂, 2D semiconducting metal-organic frameworks (MOFs), and laser-induced graphene (LIG) for high-performance NO₂ sensing. The unique hierarchical pore architecture of LIG@Cu₃HHTP₂ 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 NO₂. Consequently, LIG@Cu₃HHTP₂ shows one of the fastest responses and lowest limit of detection at room temperature compared with state-of-the-art NO₂ 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.