Programmable Polymer Memory Device Based on Hydrophilic Polythiophene and Poly(ionic liquid) Electrolyte

A three-terminal non-volatile memory device with the configuration of an organic thin-film transistor (OTFT) is constructed from two polymeric layers by using the conventional solution-coating process. It consists of a hydrophilic polythiophene, regioregular poly(3-carboxypentylthiophene) (P3CPT) as the active layer and a poly(ionic liquid), poly[1-(4-vinylbenzyl)-3-butyl imidazolium tetrafluoroborate] (PVBIT) as a polyelectrolyte layer. The conductivity of the polythiophene layer can be reversibly switched between high and low conductance states with “write” and “erase” bias at +3 and −3 V, respectively. The retention time of the ON state is up to 1.6 × 104 s and the write–read–erase–read switching is stable over 100 cycles. In addition, an instantaneous response and a fast switching speed are observed by simultaneous monitoring of both the “write” and “read” operations. All these results indicate that the device developed possesses potential applications as alternative solid-state non-volatile memory devices.