This study demonstrates the first synthesis of MXene-derived ferroelectric crystals. Specifically, high-aspect-ratio potassium niobate (KNbO3 ) ferroelectric crystals is successfully synthesized using 2D Nb2 C, MXene, and potassium hydroxide (KOH) as the niobium and potassium source, respectively. Material analysis confirms that a KNbO3 orthorhombic phase with Amm2 symmetry is obtained. Additionally, ferroelectricity in KNbO3 is confirmed using standard ferroelectric, dielectric, and piezoresponse force microscopy measurements. The KNbO3 crystals exhibit a saturated polarization of ≈21 µC cm-2 , a remnant polarization of ≈17 µC cm-2 , and a coercive field of ≈50 kV cm-1 . This discovery illustrates that the 2D nature of MXenes can be exploited to grow ferroelectric crystals.
Keywords: MAX phase; MXene-derived; ferroelectricity; hydrothermal synthesis; single crystal.
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