Stacking-Engineered Bistable Electric Polarization in a Single-Component Organoboron Molecular Crystal

Stacking-induced ferroelectricity has recently emerged as a fascinating phenomenon in unconventional van der Waals (vdW) materials. However, such a unique ferroelectric mechanism in single-molecule organic systems remains underexplored. Herein, we report the first discovery of stacking-engineered bistable electric polarization in a single-component organic crystal, 2,4,6-triphenylborazine (triphenyl-BN). In the polar triphenyl-BN crystal, the stacking of organic triphenyl-BN molecules gives rise to macroscopic polarization perpendicular to the molecular planes with a value of 0.30 μC/cm2. This polarization is generated through stacking-induced interlayer van der Waals interactions, driving the cooperative bending of phenyl groups, which is distinct from conventional polarization mechanisms. Our first-principles calculations provide theoretical insights into the polarization bistability of the triphenyl-BN crystal, and this work provides great inspiration for designing potential organic ferroelectrics through the molecular stacking strategy.