Ferroelectricity in CsPb 2 Nb 3 O 10 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 CsPb 2 Nb 3 O 10 and exfoliated 2D nanosheets. Ferroelectricity in CsPb 2 Nb 3 O 10 was demonstrated for the first time. CsPb 2 Nb 3 O 10 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 Nb 5+ ions and nearby oxygens. CsPb 2 Nb 3 O 10 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 Pb 2 Nb 3 O 10 nanosheets.