Long-Lived Efficient Delayed Fluorescence Organic Light-Emitting Diodes using n-Type Hosts
Lin-Song Cui1, Shi-Bin Ruan1, Fatima Bencheikh1,2, Ryo Nagata1, Lei Zhang3, Ko Inada1, Hajime Nakanotani1,2,4, Liang-Sheng Liao3,* & Chihaya Adachi1,2,4,*
1 Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan.
2 JST, ERATO, Adachi Molecular Exciton Engineering Project, 744 Motooka, Nishi, Fukuoka 819-0395, Japan.
3 Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano & Soft Materials (FUNSOM) & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, 215123, China.
4 International Institute for Carbon Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 MotookaNishiFukuoka, 819-0395, Japan.
Organic light-emitting diodes have become a mainstream display technology because of their desirable features. Third-generation electroluminescent devices that emit light through a mechanism called thermally activated delayed fluorescence are currently garnering much attention. However, unsatisfactory device stability is still an unresolved issue in this field. Here we demonstrate that electron-transporting n-type hosts, which typically include an acceptor moiety in their chemical structure, have the intrinsic ability to balance the charge fluxes and broaden the recombination zone in delayed fluorescence organic electroluminescent devices, while at the same time preventing the formation of high-energy excitons. The n-type hosts lengthen the lifetimes of green and blue delayed fluorescence devices by > 30 and 1000 times, respectively. Our results indicate that n-type hosts are suitable to realize stable delayed fluorescence organic electroluminescent devices.
Editor: Danting Xiang