KCl acts as a flux to assist the growth of sub-millimeter-scale metallic 2D non-layered molybdenum dioxide
Journal article, 2025

Two-dimensional (2D) metal oxides (2DMOs), such as MoO2, have made impressive strides in recent years, and their applicability in a number of fields such as electronic devices, optoelectronic devices and lasers has been demonstrated. However, 2DMOs present challenges in their synthesis using conventional methods due to their non-van der Waals nature. We report that KCl acts as a flux to prepare large-area 2DMOs with sub-millimeter scale. We systematically investigate the effects of temperature, homogeneous time and cooling rate on the products in the flux method, demonstrating that in this reaction a saturated homogenous solution is obtained upon the melting of the salt and precursor. Afterward, the cooling rate was adjusted to regulate the thickness of the target crystals, leading to the precipitation of 2D non-layered material from the supersaturated solution; by applying this method, the highly crystalline non-layered 2D MoO2 flakes with so far the largest lateral size of up to sub-millimeter scale (~ 464 μm) were yielded. Electrical studies have revealed that the 2D MoO2 features metallic properties, with an excellent sheet resistance as low as 99 Ω·square−1 at room temperature, and exhibits a property of charge density wave in the measurement of resistivity as a function of temperature. Graphical abstract: TOC (Table of Content) (Figure presented.)

Metallic

Flux method

2D non-layered materials

Thickness modulation

Metal oxide

Author

Liying Deng

Fujian Agriculture and Forestry University (FAFU)

Fuzhou University

Qing Zhang

Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)

Tianjin University

Wangyang Li

Fuzhou University

Xiao Yuan Ye

Fuzhou University

Yi Fan Zhao

Shenzhen Institute of Advanced Technology

Shen Zhong Chen

Fuzhou University

Yu Lan Wang

Fuzhou University

Xinghui Wang

Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China

Fuzhou University

Hui Peng Chen

Fuzhou University

Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China

Zhi Yang Yu

Fuzhou University

Qun Yan

Rich Sense Electronics Technology Co.

Fuzhou University

Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China

Shu Ying Cheng

Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China

Fuzhou University

Tailiang Guo

Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China

Fuzhou University

Wen Ping Hu

Tianjin University

Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)

Feng Ding

Institute for Basic Science

Ulsan National Institute of Science and Technology (UNIST)

Jie Sun

Fuzhou University

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China

Rare Metals

1001-0521 (ISSN) 18677185 (eISSN)

Vol. 44 1 404-416

Subject Categories (SSIF 2011)

Materials Chemistry

Condensed Matter Physics

DOI

10.1007/s12598-024-02898-0

More information

Latest update

1/23/2026