MXene liquid crystals (LCs) demonstrate remarkable characteristics, making them promising for applications in flexible electronics, energy storage, and biomedicine. Although MXene LCs are known to exhibit field-responsive behavior, their electro-optical (EO) properties, particularly the quantitative Kerr coefficient, its physical origin, and dynamic switching capabilities, remain unexplored, limiting their application in photonics. Here, we systematically investigate electric-field-induced ordering, response kinetics, and the giant EO Kerr effect in MXene LCs. A remarkable Kerr coefficient of up to 4.9 × 10–6 m/V2 is achieved, surpassing conventional LCs by 2 orders of magnitude and ranking among the highest reported for two-dimensional LC systems. This outstanding performance originates from the high geometric anisotropy, giant electric polarizability anisotropy, and large optical anisotropy of the MXene flakes. Furthermore, we demonstrate a proof-of-concept and dynamically switchable anticounterfeiting device enabled by this fast and reversible EO response. This work bridges the fundamental EO mechanisms of MXene LCs with their functional device potential, providing a foundation for their use in next-generation, tunable photonic technologies.
Xu et al. (Fri,) studied this question.