A highly sensitive bending sensor composed of patterned Pt lines, integrated with energy harvesting capability, is reported. The sensitivity of the bending sensor increases as the width of the Pt lines decreases, owing to the increase in crack density with decreasing line width. Furthermore, sensitivity increases with increasing bending cycles, but saturates at around 1000 cycles. Such a behavior corresponds to the increase and eventual saturation of crack density with increasing bending cycles. A microstructured polydimethylsiloxane layer is placed on top of the Pt lines to serve as a triboelectric energy harvesting layer, where human skin and the Pt lines are utilized as electrodes. Voltage and current of 18.6 V and 209 nA are generated, respectively, from gentle finger tapping. These demonstrations make the device highly useful for a wide variety of portable and wearable flexible electronic applications.

Conductive metal-organic framework (C-MOF) thin-films have a wide variety of potential applications in the field of electronics, sensors, and energy devices. The immobilization of various functional species within the pores of C-MOFs can further improve the performance and extend the potential applications of C-MOFs thin-films. However, there are currently no effective strategies for facile and scalable synthesis of high quality ultra-thin C-MOFs while simultaneously immobilizing functional species within the MOF pores. Here, we develop microfluidic channel-embedded solution-shearing (MiCS) for ultra-fast (≤ 5 mm/s) and large-area synthesis of high-quality nanocatalyst-embedded C-MOF thin-films with thickness controllability down to tens of nanometers. The MiCS method synthesizes nanoscopic catalyst-embedded C-MOF particles within the microfluidic channels, and simultaneously grows catalyst-embedded C-MOF thin-film uniformly over a large area using solution shearing. The thin-film displays highest nitrogen dioxide (NO2) sensing properties at room temperature in air amongst two-dimensional materials, owing to the high surface area and porosity of the ultra-thin C-MOFs, and the catalytic activity of the nanoscopic catalysts embedded in the C-MOFs. Therefore, our method, i.e. MiCS, can open new avenues of highly active and conductive porous materials for various applications.