Stable colloidal dispersion of functionalized reduced graphene oxide in aqueous medium for transparent conductive film.

We prepared stable colloidal suspension graphene in aqueous medium by surface modification of graphene with 4-benzenediazonium sulfonate. The sulfonate group on graphene surface interacts with water, exhibits well dispersibility and which prevents the aggregation even at neutral pH. This dispersion shows stability for three months and facile to produce films. Using such a modified graphene dispersion, transparent conductive film (TCF) has been fabricated on glass substrate by spin coating method. At appropriate concentration, the film exhibits an excellent optoelectrical property with resistivity of 1.1 kΩ with the transparency of 89% at the wavelength of 550 nm. Further, we also demonstrated the mechanical, thermal, and optoelectrical properties of prepared films.