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Home > Introduction of our tenure-track faculties > Kaji Toshihiko

Introduction of our tenure-track faculties

Kaji Toshihiko

Affiliation Institute of Engineering
Division Division of Advanced Applied Physics
Research field Organic semiconductor elecronics
Keyword(S) Organic photovoltaics, film growth, crystal growth
Research experience

・Apr.2007–Aug.2008:Postdoctral researcher, Institute for Materials Research, Tohoku University
・Sep.2008-Nov.2014: Assistant professor, Institute for Molecular Science, National Institutes of Natural Sciences
・Nov.2009-Feb.2010: Short term visiting scholar, University of Rochester
・Dec.2014-Present: Associate professor, Tokyo University of Agriculture and Technology

Educational background

・Mar.2002: B.Sc. in Chemistry, School of Science, The University of Tokyo
・Mar.2004: M.Sc. in Chemistry, School of Science, The University of Tokyo
・Mar.2007: Ph.D. in Science, School of Science, The University of Tokyo


・M&BE Award for Young Researcher (2013)
・Young Scientist Oral Presentation Award from Japan Society of Applied Physics (31st Autumn meeting, 2011)

Selected papers and publications

・T. Kaji, S. Nakao, M. Hiramoto, "Effect of Co-evaporant Induced Crystallization on Needle Growth of Phthalocyanine Thin Films", Molecular Cryst. Liq. Cryst., 578, 63-67, (2013).
・T. Kaji, M. Zhang, S. Nakao, K. Iketaki, K. Yokoyama, C. W. Tang, M. Hiramoto, "Co-evaporant induced crystalline donor:acceptor blends in organic solar cells", Adv. Mater., 23, 3320-3325 (2011).
・M. Kubo, K. Iketaki, T. Kaji, M. Hiramoto,"Conduction-type control of fullerene films from n- to p-type by molybdenum oxide doping",Appl. Phys. Lett., 98, 073311 (2011).
・T. Kaji, T. Takenobu, A. Morpurgo, Y. Iwasa, "Organic single-crystal Schottky gate transistors", Adv. Mater., 21(36), 3689-3693 (2009).
・T. Kaji, S. Entani, S. Ikeda, K. Saiki, "Origin of carrier types in intrinsic organic semiconductors", Adv. Mater., 20, 2084-2089 (2008).
・T. Kaji, T. Shimada, H. Inoue, Y. Kuinobu, Y. Matsuo, E. Nakamura, K. Saiki, "Molecular orientation and electronic structure of epitaxial bucky ferrocene (Fe(C60(CH3)5)C5H5) thin films", J. Phys. Chem. B, 108(28), 9914-9918 (2004).

Research Description

I have been studied topics below, in the field of “organic semiconductor electronics”.
1) Organic semiconductor devices (photovoltaics, transistors, diodes)
2) Structure control of organic semiconductor thin films, growth of organic crystals
3) Electronic state control of organic semiconductors
Especially in the above, recently, I am focusing on mechanism and performance of organic photovoltaic cells. Organic semiconductors, such as an ingredient of paint, have potentially high carrier mobility and ideal semiconductor characteristics when purified and crystallized. To exert these potentials in inevitably complex structure of organic photovoltaics, I will establish fabrication method of crystalline nesting structure of organic semiconductors with free-scale in nm-µm, and study on relationship of phenomena which appear in such system to physical laws.
Here, I utilize an original method “co-evaporant induced crystallization”, where liquid molecules are introduced during vacuum deposition of organic thin films. Although this method was invented for organic photovoltaics, this method can be useful for crystallization of other films. Thus, I will study on the basis of this method, in addition to the study of organic photovoltaic cells.

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About TUAT's tenure-track program

TUAT's tenure-track program has many attractive points such that tenure-track faculties can have their independent groups, and that tenured positions are prepared for all of them in advance. It is my pleasure, when thinking about my life not only during the tenure-track but after tenured, that I can supervise students and do lectures but the number of lectures and other tasks are limited. Such understandable tasks would surely make me grow as an indipendent researcher and educator.
Thanks to sincere design and management of the program, this program seems to produce the environment where the tenure-track faculties are not oversensitive to the assessment for getting tenure and the competition among them, but focus on making themselves as better project-investigators and supervisors.

Future aspirations

When talking with undergraduate students, I often remind that I decided my dream when I was their age; the dream was to make new solar cells in future. I will devote myself to research without forgetting the young mind in the beginning. To students, on the other hand, I will encourage students to study for their own dreams, and to think by themselves.