Electrolyte-gated charge accumulation in organic single crystals

Abstract

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 1mHz was 15μF∕cm2, 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 0.33hole∕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 0.23hole∕molecule.