January 11, 2019
Japan Science and Technology Agency (JST)
Keio University
Graduate School of Frontier Sciences, The University of Tokyo
Under the JST Strategic Basic Research Programs, a research group led by Associate Professor Yuya Oaki and then-graduate student Gento Nakata of the Faculty of Science and Technology at Keio University, in collaboration with PRESTO researcher Yasuhiko Igarashi and others from the Graduate School of Frontier Sciences at The University of Tokyo, has established a method to increase the yield of the process for synthesizing nanosheets by exfoliating layered structures, using materials informatics (MI).
Two-dimensional (2D) nanomaterials (nanosheets) with nanometer-scale thickness, such as graphene, have been synthesized by exfoliating their layered, stacked structures. Nanosheet materials have been attracting attention in recent years, with expectations for various applications due to their large exposed surface area, flexibility, and the potential for unique properties related to their shape.
However, this "exfoliation" process to create nanosheets also involves "breaking down" the layered material, making it difficult to improve the yield for mass production and to control the size and surface conditions, which are related to their properties.
This research group prepared layered organic-inorganic composites by pre-intercalating organic molecules between the layers (interlayers) of an inorganic layered material. By immersing these composites in various organic solvents, they investigated whether nanosheets could be obtained by breaking apart the layered material through the affinity between the interlayer molecules and the organic solvents.
In this study, experiments were conducted on layered titanium oxide by varying approximately 100 combinations of interlayer organic molecules and organic solvents, and the factors determining the nanosheet yield were extracted using sparse modeling, a data science method. Based on this learning result, 11 combinations predicted to yield nanosheets at a high rate were selected from 81 unknown combinations of interlayer organic molecules and organic solvents. As a result of synthesis under these 11 conditions, 4 conditions achieved an even higher yield exceeding 10%. This can be said to be the world's first demonstration of a method to obtain high-yield nanosheet synthesis combinations with a minimum number of experiments.
The method for improving the yield of titanium oxide nanosheets established in this study is important for accelerating the structural control and application of various nanosheet materials. Furthermore, this achievement shows that experimental scientists can accelerate the design and exploration of new materials and functions by utilizing MI, in addition to their traditional "own experience and intuition" and "own data."
The results of this research will be published in the online early view edition of the international scientific journal "Advanced Theory and Simulations" on January 10, 2019 (German time).
For the full press release, please see below.