First report on graphene oxide free, ultrafast fabrication of reduced graphene oxide on paper via visible light laser irradiation

Abstract

Conventionally, highly conductive reduced graphene oxide (rGO) is synthesized by chemical reduction of graphene oxide (GO) solution using strong toxic reducing agents. However, GO itself is synthesized using strong acids and oxidants, with repetitive cleaning and laborious steps. To overcome such challenges, this work demonstrates a novel solution to the age-old rGO synthesis route by proposing a GO free, single-step, and ultrafast rGO fabrication on paper via blue light laser irradiation, named LIrGO, for direct use in papertronic applications. Such LIrGO was thoroughly characterized, and the results were completely consistent with the conventional approach. Without any post-processing, like thermal heating or cleaning, a high carbon to oxygen ratio (7.1), narrow microfibres with mesoporous granular linked morphological structure, good electrical conductivity, and minimal sheet resistance of about 23 Ω sq−1 were obtained within few minutes based on design dimensions. With such LIrGO, various circuits and complex designs can be printed directly on paper, leading to realize environmentally friendly papertronic devices. Herein, a paper-based capacitive touch sensor was validated for excellent touch response. Further, the resulting LIrGO on paper can be hand-scraped to create composite materials for other applications. The scrapped LIrGO was leveraged to investigate the absorption capacities of PVA/rGO/Sponge and rGO/Sponge coatings over a few cycles for selective separation of oil from an oil-water emulsion. The proposed method is a beginning for a new era of rGO fabrication at a single-step avoiding all the toxic chemical routes.