Detailed analysis of amorphous organic semiconductors and creation of novel, world-first, organic semiconductor optical devices.

Highly transparent and highly smooth amorphous (noncrystalline) organic thin films are widely used in optical devices made from organic materials. However, due to the highly random state of the molecular assembly in the film, there are several unexplained points, also of academic interest. Therefore, a profound understanding of the process of formation and the assembled structure is desired. Consequently, we are proceeding with our analysis with amorphous organic semiconductor materials used in organic electroluminescent (EL) devices as our main target. Through this, we have demonstrated that rapid improvement in the characteristics of organic electroluminescent devices can be realized by controlling the state of molecular assembly (molecular orientation etc.) of the disordered film. These research results are currently widely known as one of the basic techniques of organic EL devices and their universality and originality are highly regarded both domestically and internationally.

As described above, through detailed analysis, our research aims at discovering highly universal basic techniques that can be easily applied and novel concepts that can be readily utilized in improving the characteristics of organic devices. Even among the laboratories in building 10, a conspicuous characteristic of our laboratory is our focus on “organic molecules and optoelectronic physics”, i.e., interaction between light and organic molecules, light propagation through organic devices, and control of optical and electronic properties.

Research subjects

Our research can be broadly divided into two themes: (a) detailed structural analysis of amorphous organic semiconductor thin films and elucidation of their physics (b) development of, hitherto nonexistent, novel organic semiconductor optical and electronic materials and their applications to devices. Either of the research themes are highly application oriented and constitute the challenge of creating novel techniques and general concepts (world firsts).

Wanted

• Students interested in organic semiconductor devices, who like physics
• Students who are highly ambitious either academically or technologically and who wish to polish their “individuality” as engineers.
• Students who are proactive and who can communicate their opinions and conclusions to others
• Students who are not merely not uneasy about doing things differently from others but who positively enjoy such challenges.

Contact

d_yokoyama@yz.yamagata-u.ac.jp
Laboratory visits, discussions etc. are possible at any time. To avoid disappointment due to my absence, as far as possible, please contact me by email before visiting.