Recent Progress of Singlet‐Exciton‐Harvesting Fluorescent Organic Light‐Emitting Diodes by Energy Transfer Processes

• Published in: Advanced materials (Weinheim) Vol. 31; no. 34; pp. e1803714 - n/a
• Main Authors: Byeon, Sung Yong, Lee, Dong Ryun, Yook, Kyoung Soo, Lee, Jun Yeob
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.08.2019
• Subjects: Diodes; efficiency; Emitters; Energy transfer; Excitons; Fluorescence; Materials science; Organic light emitting diodes; Phosphorescence; Quantum efficiency; Service life assessment; singlet excitons; energy transfer; efficiency; fluorescence; singlet excitons; organic light-emitting diodes
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201803714

The external quantum efficiency (EQE) of organic light‐emitting diodes (OLEDs) has been dramatically improved by developing highly efficient organic emitters such as phosphorescent emitters and thermally activated delayed fluorescent (TADF) emitters. However, high‐EQE OLED technologies suffer from relatively poor device lifetimes in spite of their high EQEs. In particular, the short lifetimes of blue phosphorescent and TADF OLEDs remain a big hurdle to overcome. Therefore, the high‐EQE approach harvesting singlet excitons of fluorescent emitters by energy transfer processes from the host or sensitizer has been explored as an alternative for high‐EQE OLED strategies. Recently, there has been a big jump in the EQE and device lifetime of singlet‐exciton‐harvesting fluorescent OLEDs. Recent progress on the materials and device structure is discussed herein. Recent progress regarding thermally activated delayed fluorescence (TADF) sensitized fluorescent organic light‐emitting diodes (OLEDs) is discussed, based on both external quantum efficiency, reported by material, and device engineering.