Fabrication of large-area and high-crystallinity photoreduced graphene oxide films via reconstructed two-dimensional multilayer structures

Graphene, the last representative sp2 carbon material to be isolated, acts as an ideal material platform for constructing flexible electronic devices. Exploring a new method to fabricate high-quality graphene films with high throughput is essential for achieving greater performance with flexible electronic devices. Here, we report a facile coating and subsequent illumination method for mass-fabricating highly crystalline photoreduced graphene oxide (PRGO) films directly onto conductive substrates. The direct fabrication of PRGO films onto Cu foils with partial oxygenated groups, an intensive stacked highly crystalline structure, and reduced graphene oxide regions enable significant performance enhancements when used as supercapacitor electrodes compared with other graphene-only devices, exhibiting high specific capacitances of 275 F g−1 at a scan rate of 10 mV s−1 and 167 F g−1 at 1 V g−1 with excellent rate capability. The as-established all-solid-state flexible supercapacitors exhibit superior flexibility and robust mechanical stability, resulting in a capacitance delay of only 2% after performing 100 bending cycles. The demonstrated PRGO films provide a promising material platform to realize a broad range of applications related to flexible electronics devices. Researchers in China have developed an improved way to make high-quality graphene films that could be used in flexible electronic devices. Hongzhi Wang, Yaogang Li and colleagues at Donghua University used a process that coats a gel of graphene oxide directly onto an electrically conducting surface such as copper. The graphene oxide is then converted into a high-quality ‘photoreduced’ graphene oxide film by exposure to light. The characteristics of the film can be finetuned by varying the ratio of graphene oxide to graphene regions. This allows improved performance in flexible electronics applications compared to graphene films made by existing methods. The fabrication process is fast, simple and low cost, making it ideal for scaling up to the industrial production levels needed for graphene to fulfil its commercial potential. Large-area and high-crystalline photoreduced graphene oxide films are fabricated by the combination of solution-processable strategy and subsequently room temperature photoreduction directly on flexible conductive substrates.