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RIKEN Center for Emergent Matter Science Emergent Molecular Function Research Group

Group Director: Kazuo Takimiya (D.Eng.)

Research Summary

Kazuo  Takimiya(D.Eng.)

Our research activity is based upon organic synthesis that can afford new organic materials utilized in optoelectronic devices, such as organic field-effect transistors (OFETs), organic solar cells (organic photovoltaics, OPVs), and organic thermoelectric devices (OTE). To this end, our team develops new organic materials, which can be designed and synthesized in order to have appropriate molecular and electronic structures for target functionalities. Our recent achievements are 1) high-performance molecular semiconductors applicable to OFETs with high mobilities, 2) new non-fullerene acceptors and their OPVs showing high power conversion efficiencies, and 3) new molecular design strategies to control packing structures of organic semiconductors.

Main Research Fields

  • Chemistry

Related Research Fields

  • Engineering

Keywords

  • Organic Semiconductors
  • Pi-electronic compound
  • Organic Synthesis
  • Organic field-effect transistor
  • Organic thermoelectric materials

Selected Publications

  • 1. K. Takimiya, K. Bulgarevich, K. Kawabata,
    "Crystal-structure control of molecular semiconductors by methylthiolation: towards ultrahigh mobility",
    Acc. Chem. Res., 34, 884 (2024).
  • 2. T. Matsuo, K. Kawabata, K. Takimiya,
    "A novel n-type molecular dopant with a closed-shell electronic structure applicable to the vacuum-deposition process",
    Adv. Mater., 36, 2311047 (2024).
  • 3. K. Bulgarevich, S. Horiuchi, K. Takimiya,
    "Crystal-structure simulation of methylthiolated peri-condensed polycyclic aromatic hydrocarbons for identifying promising molecular semiconductors: discovery of 1,3,8,10-tetrakis(methylthio)peropyrene showing ultrahigh mobility",
    Adv. Mater., 355, 2305548 (2023).
  • 4. K. Bulgarevich, K. Takimiya,
    "Crystal-structure simulation of molecular semiconductors: brickwork-related crystal structures of methylthiolated peri-condensed polycyclic aromatic hydrocarbons",
    Mater. Horiz., 10, 5492-5499 (2023).
  • 5. K. Kawabata, K. Takimiya,
    "Quinoidal Acenedichalcogenophenediones for Near-infrared-absorbing Organic Semiconductors: Effects of Chalcogen Atom Substitution on The Physicochemical and Carrier Transport Properties",
    Chem. Mater., 35, 7628–7642 (2023).
  • 6. K. Sumitomo, Y. Sudo, K. Kanazawa, K. Kawabata, K. Takimiya,
    "Enantiopure 2-(2-ethylhexyl)dinaphtho[2,3- b:2',3'-f]thieno[3,2-b]thiophenes: synthesis, single crystal structure and surprising lack of influence of stereoisomerism on thin-film structure and electronic properties",
    Mater. Horiz., 9, 444-451 (2022).
  • 7. K. Takimiya, Kirill Bulgarevich, M. Abbas, S. Horiuchi, T. Ogaki, K. Kawabata, A. Ablat,
    "“Manipulation" of crystal structure by methylthiolation enabling ultrahigh mobility in a pyrene-based molecular semiconductor",
    Adv. Mater., 33, 2102914 (2021).
  • 8. Y. Wang, K. Takimiya, “Naphthodithiophenediimide–Bithiopheneimide Copolymers for High-Performance
    n-Type Organic Thermoelectrics: Significant Impact of Backbone Orientation on Conductivity and Thermoelectric Performance",
    Adv. Mater., 32, 2002060 (2020).
  • 9. C. Wang, D. Hashizume, M. Nakano, T. Ogaki, H. Tekenaka, K. Kawabata, K. Takimiya,
    ""Disrupt and induce" intermolecular interactions to rationally design organic semiconductor crystals: from herringbone to rubrene- like pitched π-stacking",
    Chem. Sci., 11, 1573-1580 (2020).
  • 10. K. Kawabata, S. Usui, K. Takimiya,
    "Synthesis of Soluble Dinaphtho[2,3-b:2',3' -f]thieno[3,2-b]thiophene (DNTT) Derivatives: One-Step Functionalization of 2-Bromo-DNTT",
    J. Org. Chem., 85, 195-206 (2020).

Recent Research Results

Related Links

Lab Members

Principal investigator

Kazuo Takimiya
Group Director

Core members

Barun Dhara
Research Scientist
Haruki Sanematsu
Postdoctoral Researcher
Kirill Bulgarevich
Postdoctoral Researcher
Kohsuke Kawabata
Visiting Scientist

Careers

Position Deadline
Seeking a Postdoctoral Researcher (W24067) Open until filled

Contact Information

Main Research Building #510,
2-1 Hirosawa,
Wako, Saitama
351-0198, Japan
Email: takimiya [at] riken.jp

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