A polyanionic proton conductor, named poly(styrenesulfonic acid) (PSSH), is used to gate an organic field-effect transistor (OFET) based on poly(3-hexylthiophene) (P3HT). Upon applying a gate bias, large electric double layer capacitors (EDLCs) are formed quickly at the gate-PSSH P3HT-PSSH interfaces due to proton migration in the polyelectrolyte. This type of robust transistor, called an EDLC-OFET, displays fast response (<1€„ms) operates at low voltages (<1€„V). The results presented are relevant for low-cost printed polymer electronics._x000D_