Environmentally Friendly Transistors and Circuits on Paper

We created environmentally friendly low‐voltage, ion‐modulated transistors (IMTs) that can be fabricated successfully on a paper substrate. A range of ionic liquids (ILs) based on choline chloride (ChoCl) were used as the electrolytic layer in the IMTs. Different organic compounds were mixed with ChoCl to create solution‐processable deep eutectic mixtures that are liquid or semiliquid at room temperature. In the final, solid version of the IMT, the ILs are also solidified by using a commercial binder to create printable transistor structures The semiconductor layer in the IMT is also substituted with a blend of the original semiconductor and a biodegradable polymer insulator. This reduces the amount of expensive and potentially harmful semiconductor used, and it also provides increased transistor performance, especially increasing the device switching speed. These environmentally friendly IMTs are then used to create ring oscillators, logic gates, and memories on paper. Think paper! Environmentally friendly ion‐modulated transistors are built by using ionic liquids based on deep eutectic mixtures of choline chloride and different organic compounds. By using paper as a substrate and by minimizing the amount of semiconductor used, the devices are made more biodegradable and cheaper to fabricate. Inverters, ring oscillators, and more complicated circuits, such as the one‐bit memory are demonstrated.