▎ 摘　　要

We report a simple and green approach to synthesize reduced graphene oxide (RGO) nanosheets at room temperature based on Zn reduction of exfoliated GO. The evolution of GO to RGO has been characterized by X-ray diffraction, UV-Vis absorption spectroscopy and Raman spectroscopy. The results of X-ray photoelectron spectroscopy reveal that the atomic ratio of carbon to oxygen in the RGO can be tuned from 1.67 to 13.7 through controlling the reduction time. Moreover, the conductivity of the RGO is measured to be 26.9 +/- 2.2 kS/m, much larger than those previously obtained by chemical reduction through other reducing agents. More importantly, the resistance of the RGO film with 20 nm thickness can be as low as 2 k Omega/square, while a high transparency over 70% within a broad spectral range from 0.45 mu m to 1.50 mu m can be retained. The proposed method is low-cost, eco-friendly and highly-efficient, the as-prepared thinner RGO films are useful in a variety of potential application fields such as optoelectronics, photovoltaics and electrochemistry by serving as an ultralight, flexible and transparent electrode material.