Research Highlights

Transition metal dichalcogenides (TMDs) are two-dimensional materials with properties that can be shaped by their structural symmetry.

However, while concrete examples—such as the enhanced photovoltaic effects in multiwall WS₂ nanotubes, or the nonreciprocal transport in chiral WS₂ nanotubes—illustrate this structure/property relationship, precise fabrication of desired TMD structures remains a technological challenge.

In a recent article, Kato and co-workers from AIMR explored the fabrication of nanoscrolls using Janus monolayer TMDs¹.

“Typically, TMDs have a structure where a transition metal-atom layer is sandwiched between identical chalcogen-atom layers above and below,” explains Kato. “The ‘Janusification’ process aims to replace the upper chalcogen layer exclusively to break the TMD spatial inversion symmetry, yielding precise nanostructures with new properties not observed in the symmetric monolayer TMDs.”

To maximize the fabrication precision, the team used plasma-assisted surface atom substitution to prepare Janus WSSe and MoSSe monolayers, followed by a solution treatment that rolled the monolayers into one-dimensional nanoscrolls.

“In this work, we not only achieved the direct observation of the TMD Raman spectra for tuning of the Janusification conditions during reaction, but we also developed a simple liquid application and drying process that produced uniform, precise nanoscrolls of unprecedented small diameters,” says Kato.

Using this new strategy, the team is collaborating with theoretical and experimental research groups of AIMR and beyond, to develop a research field dedicated to elucidating new structure/property relationships of low-dimensional materials.

(Author: Patrick Han)