Probing Electric Field Distribution in Underlayer of an Organic Double-Layer System by Optical Second-Harmonic Generation Measurement

By analyzing the spectroscopic optical properties of an organic double-layer system comprising of pentacene and poly(3-hexylthiophene) (P3HT), the electric field distribution in a P3HT under-layer was selectively probed by microscopic optical second-harmonic generation (SHG) measurement. The double-layer system was installed as an active layer of an organic field effect transistor (OFET) with a SiO2 gate insulator, and the SH caused by the electric field formed in the P3HT layer was selectively probed at a wavelength of 450 nm. The SH signal along the OFET channel was profiled with injection charges in the off and on states, suggesting the probing of the electric field distribution in a multilayer by SHG measurement. (C) 2009 The Japan Society of Applied Physics