A facile green approach for the preparation of reduced graphene oxide (RGO), based on a non-thermal plasma jet reactor, operating in an aqueous medium under ambient conditions was developed. Argon plasma treated GO samples were systematically characterized by X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Fourier Transform Infrared (FT-IR) spectroscopy, Temperature programmed decomposition (TPD), Raman spectroscopy, and Transmission electron microscopy (TEM) techniques, which highlighted the potential of plasma approach for the formation of the RGO. The emission spectrum of the discharge confirms the in situ formation of hydrogen radicals (•H) and hydroxyl radicals (•OH), which reduce the oxygen functional groups of graphene oxide (GO), under mild reaction conditions. Raman spectroscopy confirms the optimum plasma treatment time of 6 h to deliver the best RGO (ID/IG ∼ 1.5), which also showed the highest solar cell efficiency of ∼2.3% when used as a counter electrode in a typical quantum dot sensitized solar cell. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim