Monolayer NbSe<sub>2</sub> Favors Ultralow Friction and Super Wear Resistance.

Yu, Tongtong; Shen, Ruilin; Wu, Zishuai; Du, Changhe; Shen, Xiaojun; Jia, Ning; Deng, Haoyu; Zhao, Yongkang et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

The urgent demand for atomically thin, superlubricating, and super wear-resistant materials in micro/nanoelectromechanical systems has stimulated the research of friction-reducing and antiwear materials. However, the fabrication of subnanometer-thick films with superlubricating and super wear-resistant properties under ambient conditions remains a huge challenge. Herein, high-quality monolayer (ML) NbSe<sub>2</sub> (∼0.8 nm) with ultralow friction and super wear resistance in an atmospheric environment was successfully grown by chemical vapor deposition (CVD) for the first time. Moreover, compared with few-layered (FL) NbSe<sub>2</sub>, ML NbSe<sub>2</sub> has a lower friction coefficient and better wear resistance. On the basis of density function theory (DFT) calculations, the adhesion and the degree of charge transfer between ML NbSe<sub>2</sub> and the substrate is larger than that of the topmost layer to the underlying layers of NbSe<sub>2</sub> with two or more layers, which can be used to explain that the ML NbSe<sub>2</sub> favors ultralow friction and super wear resistance.