Centers & Labs

RIKEN Center for Emergent Matter Science

Emergent Molecular Function Research Team

Team Leader: Kazuo Takimiya (D.Eng.)
Kazuo  Takimiya(D.Eng.)

The Research Team engages in the development and application of new functional organic molecules. Organic molecules can be designed and synthesized as they should have appropriate molecular and electronic structures for certain functionalities, and such functional molecules are utilized in fabricating optoelectronic devices such as organic field-effect transistors (OFETs) and organic solar cells (organic photovoltaics, OPVs). Recent our achievements are 1) development of high-performance molecular semiconductors applicable to OFETs with the highest mobilities, and 2) development of versatile semiconducting polymers that can be utilized to high performance solution-processed OTFTs and OPVs.

Main Research Field


Related Research Fields



  • Organic Semiconductors
  • Organic Field-Effect Transistors
  • Organic Solar Cells
  • Supramolecular Chemistry

Selected Publications

  1. Nakano, M., Osaka, I., Takimiya, K.:
    "Control of major carriers in ambipolar polymer semiconductor by self-assembled monolayers"
    Adv. Mater., 29, 1602893 (2017).
  2. Wang, Y., Nakano, M., Michinobu, T., Kiyota, Y., Mori, T., Takimiya, K.:
    "Naphthodithiophenediimide-Benzobisthiadiazole-Based Polymers: Versatile n-Type Materials for Field-Effect Transistors and Thermoelectric Devices"
    Macromolecules, 50, 857-864 (2017).
  3. Zafra, J. L., Qiu, L., Yanai, N., Mori, T., Nakano, M., Alvarez, M. P., Lopez Navarrete, J. T., Gomez-Garcia, C. J., Kertesz, M., Takimiya, K., Casado, J.:
    "Reversible Dimerization & Polymerization of a Janus Diradical Producing Labile CC Bonds and Giant Chromism"
    Angew. Chem. Int. Ed., 55, 14563-14568 (2016).
  4. Kawabata, K., Saito, M., Osaka, I., Takimiya, K.:
    "Very Small Bandgap π-Conjugated Polymers with Extended Thienoquinoids"
    J. Am. Chem. Soc., 138, 7725-7732 (2016).
  5. Nakano, M., Sawamoto, M., Yuki, M., Takimiya, K.:
    "N,N'-Unsubstituted Naphthodithiophene Diimide (NDTI): Synthesis and Derivatization via N-Alkylation and –Arylation"
    Org. Lett., 18, 3770-3773 (2016).
  6. Vohra, V., Kawashima, K., Kakara, T., Koganezawa, T., Osaka, I., Takimiya, K., Murata, H.:
    “Efficient inverted polymer solar cells employing favourable molecular orientation”
    Nat. Photon. 9, 403–408 (2015).
  7. Nakano, M., Osaka, I., Hashizume, D., Takimiya, K.:
    “α-Modified Naphthodithiophene Diimides-Molecular Design Strategy for Air-Stable n-Channel Organic Semiconductors”
    Chem. Mater. 27, 6418–6425 (2015).
  8. Takimiya, K., Osaka, I., Mori, T., and Nakano, M.:
    "Organic Semiconductors Based on [1]Benzothieno[3,2-b][1]benzothiophene Substructure"
    Acc. Chem. Res., 47, 1493–1502 (2014).
  9. Osaka, I., Kakara, T., Takemura, N., Koganezawa, T., and Takimiya, K.:
    "Naphthodithiophene–Naphthobisthiadiazole Copolymers for Solar Cells: Alkylation Drives the Polymer Backbone Flat and Promotes Efficiency"
    J. Am. Chem. Soc., 135, 8834–8837 (2013).
  10. Fukutomi, Y., Nakano, M., Hu, J.-Y., Osaka, I. and Takimiya, K.:
    "Naphthodithiophenediimide (NDTI): Synthesis, Structure, and Applications"
    J. Am .Chem. Soc., 135, 11445–11448 (2013)

Lab Members

Principal Investigator

Kazuo Takimiya
Team Leader

Core Members

Chengyuan Wang
Postdoctoral Researcher
Morten Jensen
Postdoctoral Researcher
Takuya Ogaki
Postdoctoral Researcher
Masahiro Nakano
Special Postdoctoral Researcher
Kohsuke Kawabata
Visiting Scientist

Contact information

504 Main Research Building,
2-1 Hirosawa,
Wako, Saitama
351-0198, Japan

Email: takimiya [at]

Related links

Recent research results

March 24, 2017: RIKEN RESEARCH
Plugging leaks in printable logic
September 30, 2016: RIKEN RESEARCH
Fluorine offers solar power boost