Indications of ferroelectric behaviour near room temperature in the organic–inorganic hybrid Q2CuBr4

Abstract

A quinuclidinium-based copper bromide molecular ferroelectric, exhibiting a polarization of P_s = 0.52 μC cm⁻² at zero electric field, has been successfully synthesized. This compound undergoes an order–disorder phase transition at T_c = 295 K, associated with thermally induced rotational motion of the quinuclidinium cations. This transition results in pronounced changes in both the dielectric constant and thermal properties. The contributions of the organic and inorganic components, as well as their interactions, to the observed electrical and thermal behaviors are discussed using both experimental data and theoretical analysis.