Eye-friendly reduced graphene oxide circuits with nonlinear optical transparency on flexible poly(ethylene terephthalate) substrates

The selective reduction of graphene oxide (GO) with direct laser writing is a rapid and efficient process to pattern conductive tracks for flexible electronic circuit applications. Here we report novel eye-friendly reduced graphene oxide (rGO) conductive tracks on transparent and flexible poly(ethylene terephthalate) (PET) substrates synthesized by one-step laser reduction of graphene oxide in an ambient environment. Resistivity as low as 1.07 × 10-4 μm has been achieved for a 20 nm thick rGO film after the industrial-grade 1064 nm Nd:YAG laser treatment. Fingerprints of the synthesized rGO were verified by Raman spectroscopy with an increased intensity ratio of the 2D band over the G band, and the deoxygenation results were examined using both X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) characterization. The rGO synthesized by this infrared laser reduction showed increased absorption toward a shorter wavelength of up to 96% in UV regions, which can significantly protect human eyes from high energy light hazards. Electronic circuit tracks with rGO synthesized with this 1064 nm laser patterning process can provide novel methods for the fabrication of future eye-friendly flexible electronics with nonlinear optical transparency.Department of Industrial and Systems Engineerin