High-density electrostatic carrier doping in organic single-crystal transistors with polymer gel electrolyte

High-density carrier accumulation in organic semiconductors is demonstrated in Au∕polymer gel electrolyte/rubrene crystal∕SiO2∕doped Si dual-gate transistors, forming electric double layers in the polymer gel. Application of only 1.2V across the polymer gel electrolyte drastically enhances the conductance of the rubrene single crystal with the field-induced carrier density up to ∼5×1013cm−2. Directly comparing the transfer characteristics of the same device channel in the dual-gate transistors revealed that the achieved doping level is beyond the maximum of the SiO2-based transistor on the opposite side of the organic crystal.