Electrolyte-gated charge accumulation in organic single crystals

Comparative studies of electrolyte-gated and SiO2-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 mu F/cm(2), which is more than two orders of magnitude larger than that of the 100-nm-thick SiO2 gate dielectric. The maximum carrier density in the electrolyte gate was 0.33 hole/molecule, which is considerably larger than that in the SiO2 gate. Furthermore, the transfer characteristics of the electrolyte-gate field-effect transistor showed reversible-peak behavior at an accumulated carrier density of 0.23 hole/molecule. (c) 2006 American Institute of Physics.