Fabrication and Electro-optic Properties of Ferroelectric Nanocrystal/Polymer Composite Films

摘要

BaTiO3(BTO),Pb(Zr_(0.52)Ti_(0.48))O3(PZT),and Sr_(1-x)Ba_xNb2O6(SBN;x=0.5,0.4,and 0.25)nanocrystal-doped polycarbonate(PC)composite thin films were prepared by a spin-coating method.Ultrafine BTO and PZT nanocrystals of pure tetragonal perovskite phase were synthesized by a hydrothermal method,while the rodlike SBN nanocrystals of pure tetragonal tungsten-bronze structure were prepared by the Pechini method.To produce better electro-optic(EO)properties through creation of noncentrosymmetry in the samples,the composite films were poled under,a high electric field at suitable temperatures.Their EO coefficients as well as transmittance spectra were measured.Both BTO/PC and PZT/PC composite films showed excellent EO properties with high EO coefficients and large figures of merit.However,SBN/PC composite films established relatively small EO coefficients due to the small transverse EO coefficients of SBN single crystals.On the basis of our results,we demonstrate that these ferroelectric nanocrystal/polymer composite films are good candidates for EO applications.