Statically Charged Electret Polymers as Solid, Nonvolatile Gates Encapsulating and Tuning Polymer Thermoelectric Parameters

We report the first example of a free-standing charged electret gate associated with a thermoelectric material. Hydrophilic polymers, the commercially available fluorocarbon polymer Novec and a cross-linked polystyrene, were charged before and after deposition of the prototypical thiophene semiconducting polymer poly(bisdodecylquaterthiophene) (PQT12), respectively. Conductivity and Seebeck coefficient were measured. The charging modulated both parameters with the expected inverse dependences on charging-induced static voltage. A tetrafluorotetracyanoquinodimethane (F4TCNQ)-doped sample and the polystyrene sample displayed Seebeck coefficients close to predictions of a general model recently proposed for polymer thermoelectrics. The freestanding gate is a possible approach to modulating polymer thermoelectrics without disrupting intermolecular packing or applying gate voltages during operation.