Direct probing of carrier motion and interfacial phenomena in organic films and devices by optical second harmonic generation and Maxwell-displacement-current

Abstract

Probing and modelling of dynamical motions of carriers in organic materials is a fundamental research subject in science and electronics. According to the Maxwell's electromagnetic field theory, electrons and dipoles are source of electric fields. As a result organic materials surrounding electrons and dipoles are polarized. By probing the dielectric polarization, we can visualize carrier motion in organic materials. An optical method based on electric-field-induced optical second harmonic generation (EFISHG) is available for directly probing the dynamical electron (and hole) transport as the migration of electric field. On the other hand, an electrical method based on the Maxwell-Displacement current generation can probe rotational dipolar motion in organic films. In this proceeding, basic concept for probing carrier motions, e.g. translational motion of electrons and rotational motion of dipoles, by paying attention to dielectric polarization phenomena is discussed. Finally, it is concluded that experiments and analyses based on dielectrics physics is a very effective way for analyzing carrier behaviours in organic films and devices.