Laser direct writing of reduced graphene oxide micropatterns and sensor applications

摘要

Micropatterns consisting of reduced graphene oxide (rGO) and graphene oxide (GO) were fabricated via laser direct writing where an insulating GO was converted to a conductive rGO by laser-induced reduction. The rGO/GO micro-interdigitated electrode showed humidity sensing behaviors. The influence of the shape and size of the rGO/GO micro-interdigitated electrode was studied to discuss the sensing mechanism and to improve the sensitivity. Three kinds of rGO(w)/GO(g) micropatterns were prepared by laser direct writing on a GO-coated PET (polyethylene terephthalate) substrate using a CW 405 nm semiconductor laser, where vv and g are the rGO electrode width and the GO gap width between rGO electrodes in micrometer unit, respectively. The humidity sensing properties of rGO(400)/GO(100), rGO(160)/GO(40). and rGO(80)/GO(20) were studied by monitoring the output voltage waveform from an electronic circuit consisting an rGO/GO interdigitated electrode and resistors in AC mode operation. The sensitivity enhancement induced by charging property of an rGO/GO interdigitated electrodes was observed accompanying transient decay of the output voltage. The shape and size of an rGO/GO interdigitated electrode remarkably influenced the humidity sensing behaviors depending on the contribution ratio of C and R parameters.