“…Graphene demonstrates unique physical and chemical properties, so it has attracted great attention since it was separated from graphite by mechanical exfoliation [1]. Up to now, graphene and its derivatives have been employed in various electronic devices, such as sensors, solar cells, photodetectors, supercapacitors and actuators [2][3][4][5][6][7][8][9]. However, although graphene and its derivatives show extraordinary talent in research field, they are still not widely used in actual production.…”