Acta Phys. -Chim. Sin. ›› 2021, Vol. 37 ›› Issue (11): 2010051.

Special Issue: Energy and Materials Chemistry

• REVIEW •

### Utilization of the van der Waals Gap of 2D Materials

Haifeng Que, Huaning Jiang, Xingguo Wang, Pengbo Zhai, Lingjia Meng, Peng Zhang, Yongji Gong()

• Received:2020-10-23 Accepted:2020-11-23 Published:2020-12-01
• Contact: Yongji Gong E-mail:yongjigong@buaa.edu.cn
• About author:Yongji Gong, Email: yongjigong@buaa.edu.cn; Tel.: +86-18513835303
• Supported by:
the National Natural Science Foundation of China(51872012);the Key Technologies Research and Development Program of China(2018YFA0306900)

Abstract:

Since their discovery, two-dimensional (2D) materials have attracted significant research attention owing to their excellent and controllable physical and chemical properties. These materials have emerged rapidly as important material system owing to their unique properties such as electricity, optics, quantum properties, and catalytic properties. 2D materials are mostly bonded by strong ionic or covalent bonds within the layers, and the layers are stacked together by van der Waals forces, thereby making it possible to peel off 2D materials with few or single layers. The weak interaction between the layers of 2D materials also enables the use of van der Waals gaps for regulating the electronic structure of the system and further optimizing the material properties. The introduction of guest atoms can significantly change the interlayer spacing of the original material and coupling strength between the layers. Also, interaction between the guest and host atom also has the potential to change the electronic structure of the original material, thereby affecting the material properties. For example, the electron structure of a host can be modified by interlayer guest atoms, and characteristics such as carrier concentration, optical transmittance, conductivity, and band gap can be tuned. Organic cations intercalated between the layers of 2D materials can produce stable superlattices, which have great potential for developing new electronic and optoelectronic devices. This method enables the modulation of the electrical, magnetic, and optical properties of the original materials, thereby establishing a family of 2D materials with widely adjustable electrical and optical properties. It is also possible to introduce some new properties to the 2D materials, such as magnetic properties and catalytic properties, by the intercalation of guest atoms. Interlayer storage, represented by lithium-ion batteries, is also an important application of 2D van der Waals gap utilization in energy storage, which has also attracted significant research attention. Herein, we review the studies conducted in recent years from the following aspects: (1) changing the layer spacing to change the interlayer coupling; (2) introducing the interaction between guest and host atoms to change the physico-chemical properties of raw materials; (3) introducing the guest substances to obtain new properties; and (4) interlayer energy storage. We systematically describe various interlayer optimization methods of 2D van der Waals gaps and their effects on the physical and chemical properties of synthetic materials, and suggest the direction of further development and utilization of 2D van der Waals gaps.

MSC2000:

• O646