Reversible Ferroelectric Polarization Modulation of Chiral Molecular Ferroelectrics by Circularly Polarized Light

The optical modulation of ferroelectric polarization constitutes a transformative, non-contact strategy for the precise manipulation of ferroelectric properties, heralding advancements in optically stimulated ferroelectric devices. Despite its potential, progress in this domain is constrained by material limitations and the intricate nature of the underlying mechanisms. Recent studies have achieved efficient regulation of ferroelectric polarization and thermal conductivity in chiral ferroelectric thin films through the application of left- and right-handed circularly polarized light (LCP and RCP). Differential absorption of circularly polarized light (CPL) induces nonequilibrium carrier dynamics, generating distinctive interfacial electrostatic fields that enable precise control of ultrathin ferroelectric films. For (R)-BINOL-DIPASi and (S)-BINOL-DIPASi (C₂₆H₂₆O₂Si), polarization changes surpass 23%, exhibiting opposite response under LCP and RCP excitation. In R chiral films, remnant polarization decreases from 1.05 µC cm^{- 2} under LCP to 0.85 µC cm^{- 2} under RCP, whereas in S chiral films, polarization increases from 0.85 µC cm^{- 2} under LCP to 0.98 µC cm^{- 2} under RCP. This reversible modulation facilitates reliable switching between ON and OFF states, presenting the potential of chiral ferroelectric materials for flexible, high-speed integrated photonic sensor technologies.