Second-Harmonic Generation in Poly(vinylidene fluoride) Films Prepared by Vapor Deposition under an Electric Field

Abstract

Second-harmonic generation (SHG) revealed the dipole orientation of poly(vinylidene fluoride) (PVDF) thin films prepared by vapor deposition in the presence of an electric field along the substrate surface. The dipole alignment was confirmed for the substrate temperatures between -130°C and 100°C under an electric field of 16 MV/m. The degree of dipole orientation estimated from the ratio of nonlinear susceptibility components depended on the deposition conditions such as the substrate temperature and the field strength. Thermal stability of the poled structure was found to be much better than that obtained by postpoling.