New way to roll atomically thin nanosheets into scrolls

By replacing the atoms on one side of the nanosheet with a different element, the team have realized a nanosheet that can spontaneously roll into a scroll when detached from its substrate.
Credit: Tokyo Metropolitan University

Janus nanosheets bring unprecedented control to preparation of nanoscrolls.

Researchers from Tokyo Metropolitan University have come up with a new way of rolling atomically thin sheets of atoms into “nanoscrolls.” Their unique approach uses transition metal dichalcogenide sheets with a different composition on either side, realizing a tight roll that gives scrolls down to five nanometers in diameter at the center and micrometers in length. Control over nanostructure in these scrolls promises new developments in catalysis and photovoltaic devices.

Nanotechnology is giving us new tools to control the structure of materials at the nanoscale, promising a whole nano-toolset for engineers to create next generation materials and devices. At the forefront of this movement, a team led by Associate Professor Yasumitsu Miyata of Tokyo Metropolitan University have been studying ways to control the structure of transition metal dichalcogenides (TMDC), a class of compounds with a wide range of interesting properties, such as flexibility, superconductivity, and unique optical absorbance.

In their latest work, they set their sights on new ways of making nanoscrolls, nanosheets rolled up into tight scroll-like structures. This is an attractive approach for making multi-walled structures: since the structure of each sheet is the same, the orientations of individual layers are aligned with each other. However, the two existing ways of making nanoscrolls have significant issues. In one, removing sulfur atoms from the surface of the nanosheet creates distortions which cause the sheet to roll up; but by doing so, they destroy the crystal structure of the sheet. In the other, a solvent is introduced between the nanosheet and the substrate, loosening the sheet from the base and allowing the formation of defect-free nanoscrolls. However, tubular structures made like this tend to have large diameters.

Instead of approaches like this, the team have come up with a new way of causing sheets to roll up. Starting with a monolayer molybdenum selenide nanosheet, they treated the nanosheet with a plasma and replaced the selenium atoms on one side with sulfur; such structures are called Janus nanosheets, after the ancient two-faced god. Gentle addition of a solvent then loosens the sheets from the base, which then spontaneously roll into scrolls due to the asymmetry between the sides. These new nanoscrolls are multiple microns in length, significantly longer than previously made single-walled TMDC nanosheets. Furthermore, they were found to be more tightly rolled than ever before, with a center down to five nanometers in diameter, meeting theoretical expectations. The scrolls were also found to interact strongly with polarized light and have hydrogen producing properties.

With unprecedented control over nanostructure, the team’s new method forms the foundation for studying new applications of TMDC nanoscrolls to catalysis and photovoltaic devices.

Journal: ACS Nano
DOI: 10.1021/acsnano.3c05681
Article Title: Nanoscrolls of Janus Monolayer Transition Metal Dichalcogenides
Article Publication Date: 17-Jan-2024

Media Contact

GO TOTSUKAWA
Tokyo Metropolitan University
totsukawa-go@jmj.tmu.ac.jp
Office: 81-426-772-829

Media Contact

GO TOTSUKAWA
Tokyo Metropolitan University

All latest news from the category: Materials Sciences

Materials management deals with the research, development, manufacturing and processing of raw and industrial materials. Key aspects here are biological and medical issues, which play an increasingly important role in this field.

innovations-report offers in-depth articles related to the development and application of materials and the structure and properties of new materials.

Back to home

Comments (0)

Write a comment

Newest articles

New technique can quickly detect fentanyl and other opioids

Testing method can analyze blood samples twice as quickly as other techniques. University of Waterloo researchers have developed a new blood testing method that can detect potent opioids much faster…

Photon upconversion: Steering light with supercritical coupling

Researchers from the National University of Singapore (NUS) have unveiled a novel concept termed “supercritical coupling” that enables several folds increase in photon upconversion efficiency. This discovery not only challenges…

Researchers harness 2D magnetic materials for energy-efficient computing

An MIT team precisely controlled an ultrathin magnet at room temperature, which could enable faster, more efficient processors and computer memories. Experimental computer memories and processors built from magnetic materials…

Partners & Sponsors