Optical properties of ferroelectric nanocrystal-containing polymer BaTiO₃/polycarbonate films

Abstract

BaTiO₃(BT)-nanocrystal-doped polycarbonate polymer composite thin films (BT/PC) with different BT concentrations were prepared by spin-coating method. Ultrafine BT (~40–50 nm) nanocrystals with pure perovskite tetragonal phase were synthesized by hydrothermal method. The structure of BT nanocrystals and composite films were studied by means of x-ray diffraction and transmission scanning microscopy. The composite films were poled with a high electric field at a suitable temperature to yield a noncentrosymmetric arrangement and produce better electro-optic properties. The poling condition under external electric field was optimized through the dielectric properties of BT and PC polymer and the effective-field intensity theory. The electro-optic (EO) coefficients and transmittance of composite films with various BT concentrations were also evaluated. The average effective linear EO coefficient and figure of merit of 20-wt % BT-doped composite films were about 63.1 and 103.1 pm/V, respectively. BT/PC composite films show excellent electro-optic properties for application in integrated optoelectronics and optics.