Center for Excitonics

Events

Exciton management in OLEDs and future organic laser diodes

April 25, 2017 at 4:30pm/36-428

Chihaya Adachi
Department of Chemistry and Biochemistry Graduate School of Engineering, Kyushu University

While the demonstration of the first OLED emitting thermally activated delayed fluorescence (TADF) in Advanced Materials1-3 in 2009 by our group gave a glimpse of TADF’s potential, our successive report in Nature4-6 in 2012 of a TADF-based OLED with an internal quantum efficiency of nearly 100% grabbed the attention of researchers world-wide and established TADF as a truly promising technology. In the first half, recent progress on TADF OLEDs will be discussed from the aspect of electroluminescence quantum efficiency and device stability.

In the second half, I will introduce our recent efforts to inject high current density, reduce roll-off related to Joule heating and various exciton annihilation processes,7-9 and control excited-state absorption for the realization of electrically pumped organic semiconductor laser diodes. By managing these issues, we report low-threshold surface-emitting organic distributed feedback lasers operating under continuous-wave photoexcitation for 30 ms.10

References: [1] Ayataka Endo, Mai Ogasawara, Atsushi Takahashi, Daisuke Yokoyama, Yoshimine Kato, Chihaya Adachi, Adv. Mater., 21, 4802, 2009 [2] Ayataka Endo, Keigo Sato, Kazuaki Yoshimura, Takahiro Kai, Atsushi Kawada, Hiroshi Miyazaki, Chihaya Adachi, Appl. Phys. Lett., 98, 083302, 2011 [3] Kenichi Goushi, Kou Yoshida, Keigo Sato, Chihaya Adachi, Nat. Photon., 6, 253, 2012 [4] Hiroki Uoyama, Kenichi Goushi, Katsuyuki Shizu, Hiroko Nomura, Chihaya Adachi, Nature, 492, 234, 2012 [5] Hajime Nakanotani, Takahiro Higuchi, Taro Furukawa, Kensuke Masui, Kei Morimoto, Masaki Numata, Hiroyuki Tanaka, Yuta Sagara, Takuma Yasuda, Chihaya Adachi, Nat. Commun., 5, 4016, 2014, [6] H. Nakanotani, T. Furukawa, C. Adachi, Adv. Opt. Mater. 3, 10, 2015. [7] H. Kuwae, A. Nitta, K. Yoshida, T. Kasahara, T. Matsushima, M. Inoue, S. Shoji, J. Mizuno, C. Adachi, J. Appl. Phys. 118, 155501, 2015 [8] M. Inoue, T. Matsushima, H. Nakanotani, C. Adachi, Chem. Phys. Lett., 624, 46, 2015 [9] K. Hayashi, H. Nakanotani, M. Inoue, K. Yoshida, O. Mikhnenko, T.-Q. Nguyen, C. Adachi, Appl. Phys. Lett. 2015, 106, 0933301 [10] Atula S. D. Sandanayaka; Kou Yoshida; Munetomo Inoue; Chuanjiang Qin; Kenichi Goushi; Jean-Charles Ribierre; Toshinori Matsushima; Chihaya Adachi, Adv. Opt. Mat., 4, 6, 834, 2016

Prof. Adachi obtained his doctorate in Materials Science and Technology in 1991 from Kyushu University. Before returning to Kyushu University as a professor of the Center for Future Chemistry and the Department of Applied Chemistry, he held positions at Ricoh Co., Shinshu University, Princeton University, and at Chitose Institute of Science and Technology. He became a distinguished professor at Kyushu University in 2010, and his current posts also include director of Kyushu University’s Center for Organic Photonics and Electronics Research (OPERA) since 2010.