An electrochemical transistor comprising an electrolyte is disclosed. The electrolyte includes an ionic liquid. In a preferred embodiment, the transistor further comprises a source electrode, a drain electrode separated from the source electrode so as to form a gap between the source and drain electrodes, a semiconductor layer bridging the gap between the source and drain electrodes to form a transistor channel, and a gate electrode separated from the source electrode, the drain electrode and the semiconductor layer. In this embodiment, the electrolyte is disposed so as to contact at least a part of both the semiconductor layer and the gate electrode.