6‐1: Invited Paper: Lifetime Improvement of TADF‐OLEDs. Issue 1 (25th September 2020) - Kim, Jun-Yun
Abstract : To enhance color purity and operational lifetime of displays, thermally activated delayed fluorescence (TADF) materials for organic light‐emitting diodes (OLEDs) have been intensively investigated. The key to success is a combination of a TADF‐based high bond dissociation energy (BDE) material as an assistant and a fluorescence‐based narrow FWHM material as an emitter. In this work, we report the R/G/B hyperfluorescence (HF)‐OLED which can emit high color purity with long operational lifetime (LT95 ). The optimized R/G‐HF‐OLEDs exhibited the LT95 of 230 hrs and 300 hrs with full width at half maximum (FWHM) of 42 and 34 nm at 12.7 and 50 mA/cm 2, respectively. Furthermore, B‐HF‐OLED reached the FWHM of 20 nm, External quantum efficiency of 20% and the LT95 of 300 hrs, which has more than doubled in efficiency of monochromic color, and nearly half in lifetime compared with B‐F‐OLED LT95 of 650 hrs at 300 nits.