MXene nanoribbons

Abstract

Quasi-one-dimensional nanoribbons have great potential for applications in nanoelectronics and nanospintronics due to their unique quantum confinement effects. In this work, first-principles calculations are carried out to predict the stability as well as magnetic and electronic properties of MXene nanoribbons with either zigzag-or armchair-terminated edges. Three types of MXene recently realized experimentally, i.e. Ti 2 C, Ti 3 C 2 and V 2 C, are considered to construct their corresponding MXene nanoribbons. In addition, the O-functionalized Ti 2 C and Ti 3 C 2 nanoribbons are also investigated. The effect of functionalization is studied by comparing different functional groups including OH, F and O. Six zigzag and two armchair families are distinguished according to different ribbon edges. Our results show that all the investigated bare MXenes are metallic and exhibit certain magnetic moments in their ground states, irrespective of the ribbon width and ribbon type. Remarkable edge reconstructions are observed for all types of nanoribbon. We further show that hydrogen passivation can lead to the increase of the magnetic moments of Ti 2 C and V 2 C nanoribbons due to charge transfer. For O-functionalized Ti 2 C nanoribbons, our calculations indicate that some of them exhibit semiconducting properties dependent on edge configurations. In particular, the band gap of armchair Ti 2 CO 2 nanoribbons with a width of 7.34A is found to be around 1.0 eV, which is significantly enhanced compared to the 0.4 eV of a pristine Ti 2 CO 2 layer. The stabilities of these nanoribbons are evaluated by virtue of their binding energies, formation energies and edge energies and we show that functionalized MXene nanoribbons are more stable than bare ribbons. Our results thus provide strong evidence for the effectiveness of nanostructuring on the electronic and magnetic properties of MXenes.

Recent advances in MXene: Preparation, properties, and applications

“…Many opportunities and challenges exist simultaneously. These include the preparation of bare MXenes; the exfoliation of new MXenes; the studies on their 1D forms [76,77]; the practical measurements of their magnetic, elastic, and optical properties; and their potential applications. All await further research efforts and increased understanding.…”

Electronic properties and applications of MXenes: a theoretical review

“…The first-principles calculations for armchair and zigzag nanoribons of pristine and functionalized Ti 2 C, Ti 3 C 2 , and V 2 C [173] have shown that i) there is a remarkable atomic reconstruction at the edges of nanoribbons, ii) hydrogen functionalization can increase magnetic moment as compared with the pristine nanoribbon, and iii) armchair Ti 2 CO 2 nanoribbon with a width of 7.34 Å exhibits a band gap of ∼1.0 eV, which is significantly larger than that of 2D Ti 2 CO 2 (∼ 0.24 eV) [39]. It is also shown that the hole and electron carrier mobility of the Ti 2 CO 2 nanoribbon can be tuned by the width as well as the edge engineering [174].…”

MXene‐Based Composites: Synthesis and Applications in Rechargeable Batteries and Supercapacitors

“…[103] Due to their excellent mechanical properties, MXenes can be applied to wearable devices. [50,106] The electronic band structure of most M n+1 X n is compact, which results in the metallic conductivity of numerous M n+1 X n flakes. [104] The electronic performance of MXene should be considered once they are seriously proposed for application in the electronic industry.…”

“…[102] Moreover, the Ti 3 C 2 T x /CNT composite shows excellent tensile properties (up to 130% strain). [106] The narrow bandgap of Ti 3 C 2 T x flakes indicates that Ti 3 C 2 T x flakes are semiconductors. [105] It is obvious that the conductivity of MXenes mainly depends on its composition.…”

“…[104] The electronic performance of MXene should be considered once they are seriously proposed for application in the electronic industry. [106] The thickness difference of Ti 3 C 2 T x flakes leads to different resistances and transmittances; therefore, their optoelectronic properties are interesting. For example, Nb 2 C, Nb 2 CF 2 , Nb 2 C(OH) 2 , and Ti 3 C 2 are metallic conductors whereas Ti 3 C 2 T x is a semiconductor.…”