Tuning the reduction and conductivity of solution-processed graphene oxide by intense pulsed light

We report about the reduction of spin-coated graphene oxide (GO) layers by intense pulsed light (IPL) treatment. The reduction is achieved in a few seconds resulting in semi-transparent graphene thin films with electrical conductivities up to 6.6 S/cm. In comparison to GO reduction by conventional thermal annealing in an oven, the IPL method is much faster, enabling applications in transparent and flexible polymer substrates. Moreover, this process is roll-to-roll compatible and chemicals-free. The parameters of IPL were optimized in order to tune the conductivity of reduced GO (rGO) films as a function of exposure energy, pulse duration, and number of pulses. The effect of IPL parameters on the morphology and the electrical properties of rGO films were investigated by vis-NIR, X-ray photoelectron, and Raman spectroscopies, as well as scanning electron microscopy, atomic force microscopy, and sheet resistance measurements. The correlation between Raman spectroscopy analysis and sheet resistance shows that the G band width can be used to evaluate the conductivity of the rGO. The IPL, in a time frame of seconds, results in higher conductivity than oven annealing of 30 min at 400 degrees C, which is also evidenced in the Raman spectra showing the same structural changes as X-ray photoelectron spectroscopy. (C) 2016 Elsevier Ltd. All rights reserved.