Title: Exciton management in OLEDs and organic laser diodes

Abstract: While the demonstration of the first OLED emitting thermally activated delayed fluorescence (TADF) in 2009-2011 by our group1-3 gave a glimpse of TADF's potential, our successive report in Nature4 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 my talk, firstly I will introduce recent progresses on TADF-OLEDs focusing on long device stability and highly efficient blue emission by engineering exciton upconversion mechanism.5.6 Further, as the post-TADF technology, I will mention the advanced light emitting technologies such as singlet fission OLED7 and perovskite based LEDs8. Finally, I will prospect for our recent efforts to realize electrically driven organic semiconductor laser diodes by solving injection of high current density, suppression of rolloffs related to Joule-heating, various exciton annihilation processes, and control excited-state absorptions, and the use of TADF mechanims9-11.

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.

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