Just take a look at our recent Nanowerk Spotlight "Nanotechnology research produces foldable graphene electronics on paper" and the referenced articles therein. These substrates are attractive because they can impart flexibility and low- cost manufacturing to devices such as transistors, circuits, light-emitting diodes, and batteries. The use of paper substrates also creates a natural opportunity to exploit another property that paper is well-known for: the ability to be folded. Foldable devices can open the door to many different types of device geometries not possible before.