Tokyo Institute of Technology · Materials Science
Professor Minoru Ashizawa's research lab specializes in the design and synthesis of novel π-conjugated semiconducting materials for organic electronics. The lab focuses on molecular engineering of conjugated polymers and small molecules—particularly those based on diketopyrrolopyrrole (DPP), thienoisoindigo (TII), and benzothienoisoindigo (BTII)—to optimize their electronic, morphological, and mechanical properties. Key research directions include tuning molecular planarity, incorporating hydrogen-bonding motifs for self-assembly, and exploring structure-property relationships in field-effect transistors and organic photovoltaics. The lab also investigates crystallization control and thin-film morphology to enhance charge transport performance.
Figures are computed from collected data and may differ slightly.
Conjugation breakers (CBs) with different H-bonding chemistries and linker flexibilities are designed and incorporated into a diketopyrrolopyrrole (DPP)-based conjugated polymer backbone. The effects of H-bonding interactions on polymer semiconductor morphology, mechanical properties, and electrical performance are systematically investigated. We observe that CBs with an H-bonding self-association constant >0.7 or a denser packing tendency are able to induce higher polymer chain aggregation and
A series of pyrene derivatives containing thienyl groups, 1−3, has been prepared using the Suzuki coupling reaction. Recrystallization from solution and physical vapor transport (PVT) method afforded different types of crystals of 1. From the mixture of isomers of 2, the 1,8-isomer preferably crystallized from solution, whereas the 1,6-isomer crystal was obtained by the PVT method. Fabricating single-crystal-based field-effect transistors of the above compounds we directly compared the field-eff
Six conjugated polymers based on thienoisoindigo (TII) and thiophene-flanked diketopyrrolopyrrole (TDPP) units bearing either branched-alkyl or siloxane-terminated alkyl solubilizing groups have been synthesized.
A novel planar π-conjugated small molecule, benzothienoisoindigo (BTII), in which additional benzene rings are fused with the thieoisoindigo (TII) unit, has been designed and synthesized.
The influence of molecular planarity on field-effect-transistor and photovoltaic cell performance in thienoisoindigo derivatives has been studied.
<italic>N</italic>-Unsubstituted thienoisoindigo and the diphenyl derivative are prepared and these molecules exhibit ambipolar performance in organic thin film transistors.
Organic materials absorbing near-infrared (NIR) light are very attractive for the fabrication of optoelectronic devices. In this study, we developed an ultralow energy gap copolymer TzQI-TDPP composed of thiadiazoloquinoxalinimide (TzQI) and thiophene-flanked diketopyrrolopyrrole (TDPP) repeat units. TzQI-TDPP has a nearly identical narrow energy gap (0.60 eV) to that of the p-channel thienoisoindigo-based homopolymer PTII. Both polymers exhibit broad and intense optical absorption in the NIR-II
Abstract Selenium-substituted TTM-TTP (2,5-bis[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene) derivatives (1a–1d), in which several 1,3-dithiole rings of the bis-fused TTF framework are replaced by 1,3-diselenole rings, have been prepared. In particular, we have accomplished the first selenium substitution of the inner TTP part (1a). The 1:1 composition iodine salt, (1a)I3, is an insulator constructed of the donor trimers. The 1:1 GaCl4 salt, (1a)GaCl4, has a uniform colu
Abstract Bis-fused TTF(tetrathiafulvalene) derivatives with a cyclohexane ring 1a-c have been synthesized. One of their radical-cation salts (1b)2Au(CN)2 exhibits high conductivity σrt=160 Scm−1 and is metallic down to 120 K. Its structure consists of weakly dimerized columns with relatively small intercolumnar interactions.
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