The University of Tokyo · Materials Science
Professor Tatsuo Hasegawa's research lab specializes in the development and characterization of organic semiconductors, with a focus on molecular design, thin-film fabrication, and field-effect transistor (OFET) devices. The lab explores novel organic semiconductors—particularly charge-transfer complexes and π-conjugated materials—aiming to achieve high-performance, single-crystalline, and ultrathin films with precise control over molecular alignment and morphology. A key innovation involves using geometrical frustration and meniscus control in solution processing to enable wafer-scale, single-molecular-layer organic semiconductor films with exceptional uniformity and electronic properties. The lab's work bridges fundamental materials science with practical applications in flexible and transparent electronics.
Figures are computed from collected data and may differ slightly.
We report ambipolar field-effect characteristics observed in metal-insulator-semiconductor field-effect transistor (MISFET) device structures based on organic single crystals of the quasi-one-dimensional (Q1D) Mott-Hubbard insulator (BEDT-TTF)$({\mathrm{F}}_{2}\text{TCNQ})$. The main aspects of the measured field-effect properties are well described by the symmetric-gate FET model, which considers the device symmetry of triode FET structures. The temperature-dependent nonlinear nature in the gat
A unique solution-based technology to manufacture self-assembled ultrathin organic-semiconductor layers with ultrauniform single-molecular-bilayer thickness over an area as large as wafer scale is developed. A novel concept is adopted in this technique, based upon the idea of geometrical frustration, which can effectively suppress the interlayer stacking (or multilayer crystallization) while maintaining the assembly of the intralayer, which originates from the strong intermolecular interactions
We report structural, electronic, and field-effect transistor characteristics of layered crystalline donor–acceptor semiconductors with dialkylated benzothienobenzothiophenes.
Meniscus, a curvature of droplet surface around solids, takes critical roles in solution-based thin-film processing. Extension of meniscus shape, and eventual uniform film growth, is strictly limited on highly lyophobic surfaces, although such surface should considerably improve switching characteristics. Here, we demonstrate a technique to control the solution meniscus, allowing to manufacture single-crystalline organic semiconductor (OSC) films on the highest lyophobic amorphous perfluoropolym
We report synthesis and examination of the electronic properties of an isomorphous series of mixed-stack organic charge-transfer complexes, composed of [bis(ethylenedithio)tetrathiafulvalene] (BEDT-TTF)-based electron donors and electron acceptors of halogen-substituted tetracyanoquinodimethanes (TCNQ's). Single crystals of ${(\mathrm{B}\mathrm{E}\mathrm{D}\mathrm{T}\ensuremath{-}\mathrm{T}\mathrm{T}\mathrm{F})(\mathrm{M}\mathrm{e}}_{2}\mathrm{TCNQ}),$ (BEDT-TTF)(ClMeTCNQ), and ${(\mathrm{B}\mat
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