Electrolyte-gated charge accumulation in organic single crystals

Comparative studies of electrolyte-gated and Si O2 -gated field-effect transistors have been carried out on rubrene single crystals by experimentally estimating their accumulated charges. The capacitance of the electrolyte gate at 1 mHz was 15 μF cm2, which is more than two orders of magnitude larger than that of the 100-nm -thick Si O2 gate dielectric. The maximum carrier density in the electrolyte gate was 0.33 holemolecule, which is considerably larger than that in the Si O2 gate. Furthermore, the transfer characteristics of the electrolyte-gate field-effect transistor showed reversible-peak behavior at an accumulated carrier density of 0.23 holemolecule.