2D Electronics Could Be One Drop Away: WPI-MANA

TSUKUBA,Japan,March 22,2021 -- A research team at WPI-MANA has developed a surprisingly simple method for fabricating highly organized mono- and multilayers of 2D nanosheets. All one needs to do the job is a pipette and a hotplate.

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Two-dimensional nanosheets have been generating a lot of excitement worldwide recently. Their broad range of unique electronic,magnetic,optical and thermal properties could find their way into next-generation devices. However,further development of 2D materials depends on finding deposition processes that enable precise layer-by-layer control of thin films while reducing time,cost and energy/sample consumption.

The team found that a simple one-drop approach improves "drop casting" fabrication of tiled nanosheets. Drop casting is one of the most versatile and cost-effective methods of depositing nanomaterials on solid surfaces. But it has serious drawbacks,including the so-called coffee-ring effect,a pattern left by particles after the liquid evaporates.

They found,to their surprise,that controlled convection by a pipette and a hotplate causes uniform deposition rather than a ring-like pattern,suggesting a new possibility for drop casting. The process is surprisingly simple -- dropping a solution containing 2D nanosheets with a simple pipette onto a substrate heated on a hotplate,followed by removal of the solution,causes the nanosheets to come together in about 30 seconds to form a tile-like layer.

The team also produced various functional coatings such as conducting,semiconducting,insulating,magnetic and photochromic coatings in multilayer,superlattice and submicrometer-thick forms,which showed the potential for a convenient way to produce high-quality 2D nanosheet films. If the process can be scaled up,it could advance development of next-generation electronics.

This research was carried out by Minoru Osada (NIMS Invited Researcher,Soft Chemistry Group,WPI-MANA,NIMS) and his collaborators.

"Single Droplet Assembly for Two-Dimensional Nanosheet Tiling"

Yue Shi et al.,ACS Nano (October 29,2020)

https://doi.org/10.1021/acsnano.0c05434

MANA E-BULLETIN

https://www.nims.go.jp/mana/ebulletin/

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