Methods of producing electrochemical transistor devices are provided, wherein a solidified electrolyte is arranged in direct contact with at least a portion of an organic material having the ability to electrochemically altering its electrical conductivity through change of redox state thereof, such that a current between a source contact and a drain contact of the transistor is controllable by a voltage applied to a gate electrode. A electrochemical transistor device is also provided, wherein an ion isolative material is provided between a solidified electrolyte and an organic material having the ability to electrochemically altering its redox state, such that a transistor channel of said transistor is defined thereby.