The Maxwell-Wagner model for charge transport in ambipolar organic field-effect transistors: The role of zero-potential position

Charge transport in an ambipolar organic field-effect transistors (OFETs) is discussed in accordance to the potential profiles reconstructed from the electric-field induced second-harmonic generation experiment. The Maxwell-Wagner model based on drift-diffusion equation in OFET is used for the potential profile analysis. A good agreement between dielectric model and the experiment suggests importance of the space-charge field effects in the design of the ambipolar light-emitting OFETs. Further, the highest enhancement of the electric field is on zero-potential position in the channel, which represents the meeting point of electrons and holes and is an origin of the electroluminescence.