BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20250625T070200EDT-1868KR5NRE@132.216.98.100 DTSTAMP:20250625T110200Z DESCRIPTION:Abstract:\n\nThrough the extensive R&D of organic light-emittin g diodes (OLEDs) for more than 30 years\, plenty of well-elaborated novel organic optoelectronic materials and device architectures have been extens ively developed\, resulting in the unique commercial utilization of OLEDs for cutting-edge smartphones\, large-area TVs\, and further new future dis play applications by taking advantage of light-weight and flexibility. Fro m the aspect of materials science\, the creation of novel light-emitting m aterials in OLEDs has been the central issue aimed at high electroluminesc ence quantum efficiency (EQE). Starting from the development of convention al fluorescence materials (1st generation) during 1990-2000th\, the room-t emperature phosphorescence (2000-) (2nd generation) and thermally activate d delayed fluorescence (TADF) (2012-) (3rd generation) continuously pionee red the novel possibilities of organic emitters\, resulted in not only hig h-performance OLEDs but also enriched organic photochemistry1). Recently\, there has been a wide variety of studies on TADF-OLEDs because of the unl imited possibilities of TADF molecular design. Further\, hyperfluorescence (HF)-OLEDs have been developed since they can realize the compatibility o f high efficiency and narrow spectral width\, which is ideal for practical display applications. Here\, we report our recent cutting-edge HP-OLEDs d emonstrating high OLED performance by optimizing host\, TADF\, and termina l emitter (TE) molecules along with the disclosure of unique exciton proce sses3-4). In particular\, we focus on the blue-emission\, which can show n arrow FWHM and high EL quantum yield. Blue HF-OLEDs based on two new TEs a re fabricated\, resulting in high external quantum efficiency (EQE) of ove r 20%\, high color purity\, and high brightness. By analyzing the transien t PL characteristics of the HP-OLEDs\, we found the presence of efficient FRET between TADF-assistant dopant (TADF-AD) and TE molecules. Further\, t ransient EL analysis confirmed that a smaller EHOMO difference between TAD F-AD and TE efficiently helps to decrease hole trapping inside the emittin g layer\, hence resulting in a lower efficiency rolloff and a longer opera tional device lifetime. In addition\, we point out that spontaneous orient ation polarization (SOP) in organic thin films is the key issue to escapin g exciton quenching processes. This report provides a designing principle for a TADF and TE in HF-OLEDs with well-matched energy levels\, leading to efficient FRET and no significant carrier trapping.\n\nIn this presentati on\, we conclusively mention the importance of the charge transfer (CT) ph enomenon in designing high-performance organic light-emitting molecules in OLEDs. Also\, CT issues are crucial in maximizing the device's operation. Further\, we look at the prospect of advanced CT technologies5-6).\n\nRef erences:\n\n[1] T. Uoyama\, et al.\, Nature\, 492\, 234 (2012)\n\n[2] C.-Y . Chan et al.\, Nature Photonics\, 15\, 203 (2021)\n\n[3] Y.-T. Lee et al. \, Advanced Electronic Materials\, 7\, 2001090 (2021)\n\n[4] M. Tanaka et al.\, ACS Applied Materials & Interfaces\, 12\, 50668 (2020)\n\n[5] R. Kab e and C. Adachi\, Nature\, 550\, 384 (2017)\n\n[6] A. S. D. Sandanayaka\, et al.\, App. Phys. Express\, 12\, 061010 (2019)\n\n \n\nBio:\n\nProf. Chi haya Adachi obtained his doctorate in Materials Science and Technology in 1991 from Kyushu University. He held positions as a research chemist and p hysicist in the Chemical Products R&D Center at Ricoh Co.\, a research ass ociate at Shinshu University\, a research staff at Princeton University\, and an associate professor and professor at Chitose Institute of Science a nd Technology. In 2005\, he returned to Kyushu University as a professor a nd was promoted to a distinguished professor in 2010\, and his current pos ts also include director of Kyushu University’s Center for Organic Photoni cs and Electronics Research (OPERA) since 2010 and director of the Fukuoka i3 Center for Organic Photonics and Electronics Research since 2013. His research has been concentrated on organic synthesis\, device fabrication\, and optical and electrical device characterization of organic semiconduct ors. He has been serving as an editor of “Organic Electronics” (Elsevier) (2007-2019) and CCS Chemistry (2019-). His publications include over 670 r esearch papers. He won Nishina Memorial Award (2017)\, Nagoya Silver Medal (2019)\, etc.\, and was selected as a highly cited researcher (Clarivate) (2018-2023) and Medal with Purple Ribbon (2023).\n\n \n\nPlease see the f ollowing link to visit the QCAM Website\n DTSTART:20240524T170000Z DTEND:20240524T183000Z LOCATION:OM 10\, Maass Chemistry Building\, CA\, QC\, Montreal\, H3A 0B8\, 801 rue Sherbrooke Ouest SUMMARY:51ԹSeminar: Chihaya Adachi- Comprehensive molecular design aime d at high-performance Optoelectronic devices URL:/chemistry/channels/event/mcgill-seminar-chihaya-a dachi-comprehensive-molecular-design-aimed-high-performance-optoelectronic -357289 END:VEVENT END:VCALENDAR