Graphene oxide (GO) is a graphene derivative with oxygen-containing functional groups in its basal plane and its borders. These functional groups facilitate GO dispersion in various solvents, including water, allowing the deposition of this material on numerous kinds of substrates and surfaces. GO contains a mixture of carbon atoms with sp2 and sp3 hybridization, which gives an insulating character to this material [1]. However, the partial reduction of oxygen-containing functional groups produces another derivative of graphene. Reduced graphene oxide (rGO) presents a certain π conjugated structure and consequent electrical conductivity [2]. rGO has been proving to be an excellent alternative to pristine graphene in electronic devices, especially in terms of cost and processability. In this study, GO sheets were deposited onto interdigitated gold electrodes and reduced via cyclic voltammetry (CV) to realize solution-gated field-effect transistors (SG-FETs) [3]. GO reduction was carried out in a conventional electrochemical cell containing the electrolyte and three electrodes: an interdigitated electrode having GO films as a working electrode, Ag/AgCl reference electrode, and a platinum plate as the auxiliary electrode. Electrochemical reduction avoids the use of dangerous reductants agents, high temperatures, and also eliminates byproducts. SG-FETs with high transconductance (over 100 µS) were achieved. In the future, the devices will be applied as sensors for the detection of cyanotoxins. Experiments in this direction are in progress.

1. Dreyer, D.R., et al., The chemistry of graphene oxide. Chemical society reviews, 2010. 39(1): p. 228-240.

2. Pei, S. and H.-M. Cheng, The reduction of graphene oxide. Carbon, 2012. 50(9): p. 3210-3228.

3. Vieira, N., et al., Graphene field-effect transistor array with integrated electrolytic gates scaled to 200 mm. Journal of Physics: Condensed Matter, 2016. 28(8): p. 085302.