Shunto Arai is an Independent Researcher at the Research Center for Macromolecules and Biomaterials, National Institute for Materials Science (NIMS). He received his Ph.D. from the University of Tokyo in 2014. He then served as a Research Associate from 2014 to 2017 and as a Lecturer from 2017 to 2022 at the same university. In 2022, he joined NIMS. His current research focuses on the hierarchical structural control of various soft-matter systems and the development of their emergent electrical, optical, and mechanical functions.

Organic semiconductors offer an ideal platform for tailor-made electronics owing to their chemical tunability and benign interfacial properties. These materials exhibit unique characteristics, such as mechanical flexibility and the ability to effectively decouple electronic systems at device interfaces, creating clean, defect-free states. While these advantages originate from weak intermolecular interactions, this weakness makes it difficult to precisely control crystal polymorphs and thin-film morphologies via self-assembly. Inspired by lipid molecules that constitute living organisms, we focused on molecules featuring π-electron frameworks unsymmetrically substituted with flexible alkyl side chains. These molecules typically form bilayer-type crystals, reminiscent of cell membranes. By manipulating side-chain degrees of freedom, we established a methodology to form an ultrathin single molecular bilayer at a wafer-size scale via self-assembly [1]. Like 2D atomic layers, the ultrathin layer can be stacked arbitrarily into molecular superlattices [2]. Furthermore, molecular interaction analysis enabled polymorph control and a microscopic understanding of phase transitions, yielding highly ordered films with efficient carrier transport properties. This presentation discusses these low-dimensional electronic systems and their integration into devices, including our recent progress in developing polymeric high-k dielectric materials.

1. S. Arai et al., Adv. Mater. 30(23), 1707256 (2018)., Adv. Funct. Mater. 30(4), 1906406 (2020), Phys. Rev. Mater. 7(2), 025602 (2023).
2. S. Arai et al., ACS Appl. Mater. Interf. (2026).