The 18th edition of Pro Invent 2020 was held on 8-20 November 2020 and organized by the Technical University of Cluj-Napoca in Romania. The patent entitled "Fabrication of flexible graphene oxide electrodes by laser radiation" received the Gold Metal in this international competition.

The method, developed by researchers at ICMAB and at the University Babes-Bolyai (Romania), consists of a low-cost manufacturing procedure of flexible graphene oxide electrodes using laser radiation. The electrodes obtained, planar and with a low electrical resistance and high capacitance are ideal for electrochemical sensor applications and supercapacitors for energy storage. 

Graphene-based electrodes

Graphene-based materials have extraordinary electrical, mechanical and thermal properties, which make them special for applications in flexible electronics and electrochemical devices.

For its lower cost and higher dispersibility, graphene oxide (GO) with its subsequent reduction (rGO) is the most used. However, the reoxidation and pyrolysis of rGO when exposed to high temperatures is a
inconvenient when making stable electrodes. The present method proposes an alternative technique to obtain a rGO stable by laser radiation.

The method consists of irradiating with visible light a GO membrane deposited on a flexible polymeric support, protected on both sides with transparent sheets to the visible light, whose function is to eliminate oxygen reabsorption and prevent the reoxidation and pyrolysis of rGO. After the process, the irradiated area becomes rGO, while the non-irradiated area remains intact as GO, being possible the design of electrodes with different patterns

Simple, scalable and potential applications

The treatment conditions significantly reduce the resistance of the material and increase its electrochemical response In addition, the obtained rGO possesses great mechanical stability and adherence to the substrate.

The main advantages of the method are its low-cost and simple production, its scalability, the abscence of toxic compounds, the room temperature conditions, and the potential energy and sensor applications of the material obtained. 

The paper "New fabrication method for producing reduced graphene oxide flexible electrodes by using a low-power visible laser diode engraving system" published in Nanotechnology (IOP Publishing) features and explains with more details this method.  

Reference:

New fabrication method for producing reduced graphene oxide flexible electrodes by using a low-power visible laser diode engraving system
A. Chuquitarqui, L.C. Cotet, M Baia, E. György, K. Magyari, L. Barbu-Tudoran, L. Baia, M. Díaz-González, C. Fernández-Sánchez and A. Pérez Del Pino
Nanotechnology, 31, 32, 2020. DOI:10.1088/1361-6528/ab8d67