Multifunctional metal–organic frameworks nanoengineered laser-induced graphene for health electronics

Laser-induced graphene (LIG) has great application potential in flexible electronics. Incorporating other functional nanomaterials into LIG is an important way to improve its performance. However, there are few studies on in-situ modification of LIG morphology by nanomaterials to improve its performance. Herein, to modify the morphology of LIG films, NiCo-metal–organic frameworks (NiCo-MOFs) were added to the LIG precursors to participate in the carbonization forming process of LIG films for the first time, and the NiCo nanoporous carbon (NiCo-NPC)/LIG films with cauliflower-like surface microstructure were obtained. Since the formation process of LIG is affected by the carbonization of NiCo-MOFs, the NiCo-NPC/LIG film has a fluffier porous structure and rougher surface morphology than that of the LIG film. Therefore, the NiCo-NPC/LIG-based flexible piezoresistive sensor exhibits an ultra-high sensitivity of 226 kPa−1 in 0–45 kPa, which is 54 % higher than that of the LIG-based sensor. Meanwhile, the NiCo-NPC/LIG film exhibits an electromagnetic interference (EMI) shielding effectiveness of 171 dB/mm in the band of 8.2–12.4 GHz, which is 104 % higher than that of the corresponding LIG film. In addition, the NiCo-NPC/LIG-based Joule heater exhibits fast response and good flexibility. The experimental results indicate that using MOFs additives to modify the morphology of LIG in situ can effectively improve LIG performance, which provides a new way for developing high-performance LIG-based composite films.