Fabrication of ultrathin, free-standing, transparent and conductive graphene/multiwalled carbon nanotube film with superior optoelectronic properties

• A wet chemical method to obtain transparent electrodes for optoelectronic devices
• Effect of graphene/multiwalled carbon nanotubes (MWCNTs) ratio studied
• The ratio σdc/σopt is enhanced to 10.27.
• The hybrid films showed transmittance up to 87.3% at 550 nm and 87.9% at 800 nm.
• Graphene/MWCNTs film showed lowest sheet resistance of 136 Ω/sq.

Here we report a wet chemical technique to obtain transparent electrodes for optoelectronic devices. This technique is simple, facile, low cost and an effective way to prepare ultrathin free standing hybrid graphene/multiwalled carbon nanotubes (MWCNT) films. The graphene/MWCNT films, up to 36 mm in diameter, with controllable thickness and root mean square surface roughness of the order of 12.6 nm are prepared. The ratio of graphene/MWCNT is optimized to make them free standing and easily transferrable on various substrates. The ratio of direct current conductivity to the optical conductivity (σdc/σopt) which is considered as figure of merit for transparent conductors, is enhanced to 10.27 for graphene/MWCNT hybrid films. The prepared films showed outstanding transmittance up to 87.3 ± 1% at 550 nm, 87.9 ± 1% at 800 nm and sheet resistance of 136 ± 22.4 Ω/sq.