A 2D Van Der Waals Molecular Ferroelectric

) cantilevers in the adjacent two monolayers. More strikingly, it can show robust room-temperature ferroelectricity even in a mechanically exfoliated ultrathin flake as thin as 9 nm, which has never been achieved in traditional molecular ferroelectrics with ferroelectricity mainly in the bulk form and micron-scale thin film. To the best of the knowledge, 2,2,3,3-TFPS is the first molecular 2D vdWs ferroelectric showing robust ferroelectricity in sub-10 nm thickness. This work expands the diversity of 2D vdW ferroelectrics and sheds light on the exploration of molecular 2D vdW ferroelectrics with promising low-dimensional ferroelectricity for applications in nanoscale devices.