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RIKEN Center for Emergent Matter Science Emergent Functional Polymers Research Team

Team Leader: Keisuke Tajima (Ph.D.)

Research Summary

Keisuke  Tajima(Ph.D.)

We work on the development of new organic semiconducting polymer materials and their application to organic electronic devices. Specifically, we seek the methodology and the molecular design to control the precise structures in molecular- and nano-scale at our will, and try to find breakthroughs to drastically enhance the performance of the organic electronic devices. Targets of our research are not only the conventional organic solar cells and field-effect transistors, but also the organic electronic devices with new functions based on the structure controls.

Main Research Fields

  • Chemistry

Related Research Fields

  • Engineering


  • Organic solar cells
  • Semiconducting organic polymers
  • Thin films
  • Nanostructures
  • Interfacial science

Selected Publications

  • 1.Heo, S.W., Le, H.H.T., Tanaka, T., Osaka, I., Takimiya, K., and Tajima, K.:
    "Cumulative Gain in Organic Solar Cells by Using Multiple Optical Nanopatterns"
    J. Mater. Chem. A 5, 10347-10354 (2017)
  • 2.Huang, J., Nakano, K., Suzuki, K., Chen, Y.J., Wang, F.J., Koganezawa, T., and Tajima, K.:
    "π-Conjugation Effects of Oligo(thienylenevinylene) Side Chains in Semiconducting Polymers on Photovoltaic Performance"
    Macromolecules 50, 3557-3564 (2017)
  • 3.Chen, P.H., Nakano, K., Suzuki, K., Hashimoto, K., Kikitsu, T., Hashizume, D., Koganezawa, T., and Tajima, K.:
    "Organic Solar Cells with Controlled Nanostructures Based on Microphase Separation of Fullerene-attached Thiophene-Selenophene Heteroblock Copolymers"
    ACS Appl. Mater. Interfaces 9, 4758-4768 (2017)
  • 4.Nakano, K., and Tajima, K.:
    "Organic Planar Heterojunctions: From Models for Interfaces in Bulk Heterojunctions to High-Performance Solar Cells"
    Adv. Mater. 29, 1603269 (2017)
  • 5.Nakano, K., Suzuki, K., Chen, Y.J., and Tajima, K.:
    "Roles of Energy/Charge Cascades and Intermixed Layers at Donor/Acceptor Interfaces in Organic Solar Cells"
    Sci. Rep. 6, 29529 (2016)
  • 6.Nakano, K., Nakano, M., Xiao, B., Zhou, E.J., Suzuki, K., Osaka, I., Takimiya, K., and Tajima, K.:
    "Naphthodithiophene Diimide-Based Copolymers: Ambipolar Semiconductors in Field-Effect Transistors and Electron Acceptors with Near-Infrared Response in Polymer Blend Solar Cells"
    Macromolecules 49, 1752-1760 (2016)
  • 7.Zhong, Y. F., Suzuki, K., Inoue, D., Hashizme, D., Izawa, S., Hashimoto, K., Koganezawa, T., and Tajima, K.:
    "Interface-induced Crystallization and Nanostructure Formation of [6,6]-Phenyl-C61-butyric Acid Methyl Ester (PCBM) in Polymer Blend Films and Its Application in Photovoltaics"
    J. Mater. Chem. A 4, 3335-3341 (2016)
  • 8.Wang, F., Hashimoto, K., and Tajima, K.:
    "Optical Anisotropy and Strong H-Aggregation of Poly(3-Alkylthiophene) in a Surface Monolayer"
    Adv. Mater. 27, 6014-6020 (2015)
  • 9.Izawa, S., Nakano, K., Suzuki, K., Hashimoto, K., and Tajima, K.:
    "Dominant Effects of First Monolayer Energetics at Donor/Acceptor Interfaces on Organic Photovoltaics"
    Adv. Mater. 27, 3025-3031 (2015)
  • 10.Zhong, Y. F., Izawa, S., Hashimoto, K., Tajima, K., Koganezawa, T., and Yoshida H.:
    "Crystallization-Induced Energy Level Change of [6,6]-Phenyl-C61-Butyric Acid Methyl Ester (PCBM) Film: Impact of Electronic Polarization Energy"
    J. Phys. Chem. C 119, 23-28 (2015)

Recent Research Results

Related Links

Lab Members

Principal investigator

Keisuke Tajima
Team Leader

Core members

Jianming Huang
Postdoctoral Researcher
Soo Won Heo
Postdoctoral Researcher
Chao Wang
Postdoctoral Researcher
Chiho Katagiri
Postdoctoral Researcher
Kyohei Nakano
Special Postdoctoral Researcher
Masamichi Fujihira
Senior Visiting Scientist
Kouki Akaike
Visiting Scientist
Akira Ohno
Visiting Scientist
Fanji Wang
Junior Research Associate

Contact Information

N301-1, Chemistry and Materials Physics Building,
2-1 Hirosawa, Wako,
Saitama 351-0198, Japan
Email: keisuke.tajima [at] riken.jp