Ferroelectricity in CsPb₂Nb₃O₁₀ and exfoliated 2D nanosheets

Pb-based perovskites play pivotal roles in ferroelectric research. In the search for new Pb-based ferroelectrics, we investigated the ferroelectric properties of Dion-Jacobson type CsPb₂Nb₃O₁₀ and exfoliated 2D nanosheets. Ferroelectricity in CsPb₂Nb₃O₁₀ was demonstrated for the first time. CsPb₂Nb₃O₁₀ adopted a polar tetragonal structure with a modest T_C = 260 °C and polarization P_S = 7.93 μC cm^-2; the polarization mainly arose from the out-of-plane displacements of Nb⁵⁺ ions and nearby oxygens. CsPb₂Nb₃O₁₀ layered perovskite offers additional advantages for tailoring ferroelectric nanomaterials, as exfoliated 2D nanosheets provide novel platforms for investigating ferroelectric properties down to the 2D limit. Piezoresponse force microscopy confirmed stable ferroelectricity even in exfoliated 2D Pb₂Nb₃O₁₀ nanosheets.