Daisuke Yokoyama

Daisuke Yokoyama Address
Graduate School of Science and Engineering, Yamagata University
TEL +81-238-26-3890
E-mail d_yokoyama [--at--] yz.yamagata-u.ac.jp
Post Dec.01.2009 —
Research Field Organic photophysics, Quantum chemistry, Organic device optoelectronics
Key Words
Organic light-emitting diodes (OLEDs), Organic photovoltaic cells (OPVCs), Spectroscopic ellipsometry, Molecular orientation, Intermolecular interactions, Organic amorphous films
Research Interests
Organic vacuum-deposited films, which are commonly used in OLEDs and OPVCs, have no restriction on the underlying layer, making it possible to fabricate multilayer structures with a high functionality using many kinds of materials. This is a notable feature of vacuum-deposited films when compared with liquid crystal and polymer materials.
Recently, I have studied the molecular orientation in vacuum-deposited organic semiconductor films and found that the molecules of the organic semiconductor are generally oriented even in vacuum-deposited amorphous films. This result overrides the assumption that the molecular orientation should be random in the organic amorphous films in OLEDs, which has been believed for around 20 years since the beginning of the research in OLEDs. Now, I am trying to enhance the performances of OLEDs and OPVCs utilizing the molecular orientation effectively.
I started to study in Yamagata University in December, 2009. I hope that I will soon be able to show you fruitful achievement that can contribute to the development of the study in this field.
For the further development, it is important to control intermolecular interactions and the subsequent molecular orientation in devices, which leads to the control of electrons and light in them. I believe that the control in a higher level is necessary for organic devices to coexist with inorganic devices which have been developed for a long time to obtain the very high controllability. By studying the detail of organic films and devices in molecular level, I will try to clarify the device physics in organic devices.
I also welcome to do a collaborative study with a group in other universities and companies. I hope that we can develop the research in this field together by complementary cooperation.