Fabrication of Robust Paper-Based Electronics by Adapting Conventional Paper Making and Coupling with Wet Laser Writing

Paper offers the potential as a sustainable substrate for electronics, yet a key remaining challenge is patterning. While most demonstration studies pattern by printing conducting inks onto cellulose, we adapt conventional paper making to create a stable non-conducting composite of graphene oxide (GO; 30%) and cellulose (70%) and then pattern this composite using wet laser writing. Specifically, the GO/cellulose composite is as follows: soaked in a HAuCl4 solution; laser patterned to simultaneously reduce GO (rGO) and generate metallic gold seeds (typical writing speed 20 s·cm–2); and then incubated (30 min) in HAuCl4 solution to "grow" gold nanoparticles (Au NPs) in the pre-seeded patterned region. Various methods demonstrate that laser patterning induces spatially selective chemical changes in the composite. Functionally, the patterned region (Au NPs/rGO/cellulose) shows a 200-fold increase in conductivity (1362 S m–1) compared to the unpatterned region (GO/cellulose). As a simple demonstration, we fabricated patterned composite paper electrodes and demonstrate excellent electrochemical sensing performance in terms of sensitivity, selectivity, stability, and repeatability. We envision that laser patterning of composite paper offers unprecedented opportunities for scalable manufacturing because conventional papermaking can generate the stable substrate and laser patterning can be extended from serial writing to parallel photolithographic methods common in electronics fabrication.