Preparation of environmentally stable graphene circuits for flexible light-emitting diodes using patterned laser direct writing

Abstract

Flexible technology incorporating materials and manufacturing processes has attracted the attention of researchers and commercial entities. The study showed that using a laser to reduce graphene oxide patterns from a graphene-based composite film was an effective method for creating highly conductive flexible circuits for light-emitting diodes. The composite of graphene oxides/polyimide (GO/PI) could be a precursor for a flexible reduced graphene circuit by optimizing the ratio of GO/PI to 50 wt% GO and adjusting the focus depth to 13 % and packed density to 10 using a low-powered semiconductor laser. The laser effectively reduced GO into graphene and removed the oxygen-containing groups, resulting in a significant increase in carbon content from 72.58 % (C/O ratio of ∼ 3.20) to 83.43 % (C/O ratio of ∼ 5.96). It achieved a low resistance of the circuit at 19.76 Ω/sq while maintaining the stable flexibility of the polymer matrix, enabling a substrate-integrated circuit without any packaging in the air for flexible electronic devices. The demonstrated flexible circuit for light-emitting diodes showed good reliability and flexibility, enduring bending at 60 degrees over 150 cycles in 30 min. This versatile technique provided an innovating method for flexible graphene-based electronic circuits through digital patterned laser engraving in research and industrial applications.