Using three common materials – light cardboard, a pencil and Teflon tape – the researchers built a device with an area of 8 cm² that can generate more than 3 V and supply enough current to power a simple LCD. The generator operates entirely with static charge, utilizing the electron displacement effect which occurs when two insulating materials, such as cardboard and Teflon, touch each other. The generator devised by the researchers consists of two small cards with one side coated with graphite from a pencil. Each pf these graphite layers serves as an electrode. Teflon tape is applied to the other side of one of the cards, and then the cards are stacked like a sandwich with the Teflon layer in the middle and taped together slightly arched, so the two insulator surfaces do not touch (see the video).
If you press the cards together with you finger, the two insulators touch each other and generate a static charge. When you remove your finger, the cards move apart again and the static charge flows through the graphite electrodes into a connected capacitor. To boost the capacity of the generator, the researchers imprinted the insulator surfaces with sandpaper to increase the surface area. This resulted in six times as much output power.