Figure 2: Electrode characterizations.

(a) Electrical impedance spectra for CLEAR and platinum micro-ECoG devices in saline. The x axis represents real impedance and y axis represents imaginary impedance. Each point was taken at a different frequency, between 10 Hz and 31 kHz. (b) Average CV results over 16 electrode sites on CLEAR, gold and platinum micro-ECoG arrays. (c) Average CV results for 16 electrode sites on CLEAR and gold micro-ECoG arrays. (d) Average artefact effect test results for CLEAR and platinum micro-ECoG devices, with light applied to a single electrode site on each device via an optical fibre attached to a blue laser, with an application of 63.7 mW mm⁻² power for 3 ms. (e) Trend of sheet resistance as a function of the number of graphene layer. The error bar represents the s.d. of sheet resistance extracted from five sample measurement. (f) Light transmittance test results for 76 Ω per square four graphene monolayers on a 15-μm Parylene C film (CLEAR), 76 Ω per square four graphene monolayers only (Graphene), Parylene C film only (Parylene), 60 Ω per square ITO/PET and 100 76 Ω per square ITO/PET film. (g) Transmittance versus sheet resistance graph for various conducting materials (graphene, ITO, ultrathin metals).