TPU Scientists: Silver Decoration Improves Properties of 2D-Materials

The research was supported by a grant from the Russian Foundation for Basic Research. The research findings have been published in the Communications Chemistry (Q1; IF:7,2).

Metallic nanoparticles are potentially applicable in photocatalysis, sensorics, and optoelectronics. They enhance interaction of light with matter, boost optoelectronic response, and improve the photocatalytic performance of 2D materials. In the past, however, nanoparticles were commonly deposited on the plane of 2D layers, which disrupted their crystalline structure.

Researchers from the TERS-Team research group at the Research School of Chemistry and Applied Biomedical Sciences have developed a new method of creating heterostructures. It consists in photoinduced edge-specific nanoparticle decoration of two-dimensional materials rather than the plane. In the study, the scientists used tungsten diselenide, a promising inorganic compound that belongs to the class of 2D materials. It is a thin structure of several atomic layers, a semiconductor, which means it can be used for electronic devices. Since the layer edges are the active center for catalytic reaction and electron transfer, depositing metal nanoparticles selectively on the edges of 2D-materials simplifies the electron transfer process and improves efficiency in catalysis, electronics and optoelectronics.

We deposited silver nitrate on the surface of tungsten diselenide nanoribbons and exposed it to laser treatment. We found that the presence of tungsten diselenide is a key factor for the reduction of silver ions to metallic silver. This occurs due to strong light absorption of tungsten selenide. It results in the formation of silver nanoparticles with an average diameter of 32 nm. Our method is simple and allows for selective deposition of metallic nanoparticles at the edges of tungsten selenide-based nanoribbons, and also, presumably, other 2D materials such as graphene, tungsten disulfide, and molybdenum disulfide,

As part of the research, they have studied the dependence of nanoparticle formation on laser radiation parameters, the mechanism of their deposition, as well as the photocatalytic activity of the resulting structures.

The proposed method of laser-assisted decoration can be used in combination with other methods and applied to different 2D-materials. It can be effectively used to design, model, improve and investigate complex micro- and nano-properties of materials and systems.

"Since the particles are deposited on the edges, the nanoribbon structure remains intact. Silver nanoparticles can interact with light in such a way that they act as nanoscale sources of light. This property opens up the opportunity to use them in the creation of phototransistors and high-performance catalytic systems," summarizes Raul Rodriguez, professor at the Research School of Chemistry and Applied Biomedical Sciences of Tomsk Polytechnic University.