A new organic–inorganic hybrid perovskite ferroelectric [ClCH2CH2N(CH3)3][PbBr3] and Its PVDF matrix-assisted highly-oriented flexible ferroelectric films

Abstract

A new organic–inorganic hybrid perovskite ferroelectric, [ClCH₂CH₂N(CH₃)₃][PbBr₃] (CEPbBr) was obtained by the reaction of (2-chloroethyl) trimethylammonium chloride [ClCH₂CH₂N(CH₃)₃]⁺Cl⁻ with lead(II) bromide in a HBr aqueous solution. CEPbBr could undergo a reversible phase transition at 315/300 K with the space group change from Cc to Pna2₁ and exhibit the dielectric, SHG, and ferroelectric triple transitions between high and low states as a response to a temperature stimulus. The experimental spontaneous polarization (P_s) before and after phase transition for the single crystal sample is 6.20 μC cm⁻² and 0.28 μC cm⁻², respectively. In order to solve the problem of randomly distributed dipole orientation of powder-pressed pellet, highly-oriented flexible ferroelectric films were obtained by the method of β-phase dominated PVDF matrix-assisted in situ growth of CEPbBr particles. The protocol of inducing a preferred orientation by a polymer matrix may be key to developing highly-oriented flexible ferroelectric thin films for electronic applications.