We will post a report on the activities of student who received overseas travel support from the Integrated Initiative for Designing Future Society in 2024FY.
It seems that the overseas training program was a great opportunity for future research and career development.
Report for overseas training supported by Integrated Initiative for Designing Future Society
“Report on activities at the Technical University of Munich”
Kosuke Anraku
Photochemical Technology Innovation Group
Interdisciplinary Graduate School of Science and Engineering Integrated Science and Engineering
Kyushu University
Research questions and travel objectives
In previous work, in collaboration with Associate Professor Jian Albrecht and the group of Professor Rubén D. Costa at the Technical University of Munich, the current supervisor of my laboratory, we have successfully developed long-life electrochemiluminescent cells (LECLECs) using dendrimers, which are dendritic polymers, as light-emitting materials. This Dendri LEC (LECLEC using dendrimers), which emits yellow light, has the longest lifetime of any device using purely organic light-emitting materials, but its luminance is low and improvement has been sought. Based on this, the luminescence quantum yields (PLQYPLQY) of three newly designed and synthesised yellow-emitting dendrimers with different terminal substituents were measured in thin films, and one of them showed a PLQY about twice that of the dendrimer in the previous study, indicating that an improvement in luminance is expected in LEC applications.
During this stay, the newly designed and synthesised dendrimers were used to develop long-life and high-brightness LECs.
Activities
During this stay, the focus was on the fabrication of LECs using dendrimers and the evaluation of device performance.
LECs belong to the same class of field emission devices as OLEDs, and are single-layer devices consisting of a light-emitting layer composed of a mixture of light-emitting materials, electrolyte and organic polymers, sandwiched between electrodes. In the laboratory of Professor Rubén D. Costa, who has published extensively on LECs, a wide range of experiments are possible, including LEC fabrication, device evaluation, thin film morphology observation, electrochemical measurements and spectroscopy.
In fact, an attempt was made to optimise the LEC device by using newly developed dendrimers and changing the types of organic polymers and their ratios as appropriate. As a result, we succeeded in developing LECs with higher luminance than in previous studies, but further improvement of the device lifetime was an issue.
As a future prospect, the degradation mechanism of LECs should be investigated in order to develop LECs with high levels of both luminance and lifetime.
The development of LECs with high levels of luminance and lifetime will be investigated by studying the degradation mechanisms of LECs (Photos 1-3).
In addition, oral and poster presentations were made at workshops and international conferences attended during the trip, and discussions with researchers in other fields as well as those in the immediate vicinity provided unprecedented insights and knowledge leading to future research activities (Photo 4).
Lessons and impressions from the activities
In his previous research, he had mainly synthesised designed molecules and evaluated their fundamental optical properties, but during this fellowship he carried out application-oriented research by fabricating light-emitting devices based on these fundamental properties. Having experienced actual device fabrication, I am convinced that in the future I will be able to design molecules and evaluate their physical properties with a more concrete picture of the issues involved in device applications. Through this activity, I have also learnt the importance of English conversation skills, even though they are very rudimentary. In Professor Rubén D. Costa’s lab, where members of different nationalities come together, English is naturally the common language of the lab. Discussions in the lab were conducted in English, and I was required to accurately read the arguments of others and accurately convey my own arguments in the course of my own research, which provided me with a unique opportunity to review my English language skills. I felt this strongly not only in my daily research activities, but also in the workshops and international conferences I attended during my trip. I would like to make even greater efforts based on this experience because I was able to realise it as an experience.
