Chihaya Adachi: Delayed fluorescence in new OLED molecules offers 100% quantum efficiency
Chihaya Adachi is director of the Center for Organic Photonics and Electronics Research (OPERA) in the Center for Future Chemistry at Kyushu University (Japan). He received his M.Eng (1988) and D.Eng (1991) in Materials Science and Technology from Kyushu University.
Usage of organic phosphorescence molecules is key to OLED technology. Although OLEDs using fluorescence materials have achieved high reliability, electroluminescence (EL) efficiencies are low because of the limitation of singlet exciton production efficiency (~25%) by electrical excitation. Since the exciton production ratio under electrical pumping is 1:3 for the singlet-to-triplet exciton, phosphorescence materials are crucial for high EL efficiency. Recently OLEDs using phosphorescence materials have achieved exciton production efficiency of ~100%, resulting in 20% external EL efficiency.
Adachi gave a keynote presentation at SPIE Photonics West 2013 on "Third-generation organic light-emitting diodes." In 2005, Adachi received a Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology, Science and Technology for studies on organic electroluminescence.