MXene-Derived Ferroelectric Crystals.

Tu, Shaobo; Ming, Fangwang; Zhang, Junwei; Zhang, Xixiang; Alshareef, Husam N · Adv Mater · 2019

basic_science · Level V

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Abstract

This study demonstrates the first synthesis of MXene-derived ferroelectric crystals. Specifically, high-aspect-ratio potassium niobate (KNbO<sub>3</sub> ) ferroelectric crystals is successfully synthesized using 2D Nb<sub>2</sub> C, MXene, and potassium hydroxide (KOH) as the niobium and potassium source, respectively. Material analysis confirms that a KNbO<sub>3</sub> orthorhombic phase with Amm2 symmetry is obtained. Additionally, ferroelectricity in KNbO<sub>3</sub> is confirmed using standard ferroelectric, dielectric, and piezoresponse force microscopy measurements. The KNbO<sub>3</sub> crystals exhibit a saturated polarization of ≈21 µC cm<sup>-2</sup> , a remnant polarization of ≈17 µC cm<sup>-2</sup> , and a coercive field of ≈50 kV cm<sup>-1</sup> . This discovery illustrates that the 2D nature of MXenes can be exploited to grow ferroelectric crystals.