Realizing Efficient Deep Blue Light-Emitting Diodes and Single Component White Light-Emitting Diodes with Low Efficiency Roll-Offs from Anthracene-Based Organic Emitters

Purely organic emitters that can efficiently utilize triplet excitons are highly desired for organic light-emitting diodes (OLEDs). Hot exciton channel has emerged as a competitive strategy for the efficient harvest of triplet exciton to improve the OLEDs performance and suppress efficiency roll-off in devices. Here, two deep blue emitters, OPACN and SPACN are designed and synthesized, employing diphenylanthracene (PAnP) unit as central core, sp3 hybridized O and S atom as conjugation blocker, and electron-withdrawing cyano group as intramolecular charge transfer (ICT) introducer. Especially, OPACN presents bluer emission with electroluminescence (EL) peak at 436 nm, CIE coordinates of (0.16, 0.10), and a maximum external quantum efficiency (EQE) of 8.7%, while SPACN shows an EL peak at 444 nm, CIE coordinates of (0.17, 0.12) and a maximum EQE of 9.0%. Furthermore, the single-component white organic light-emitting diode (WOLED) based on OPACN exhibits dual emission from monomer and excimer with EQE of 5.4%. And even the luminance increases to 1000-10 000 cd m-2, the EQE still remains as high as 5.2% and 4.4%, respectively, showing very low efficiency roll-offs. These results demonstrate an alternative approach for designing high-performance deep blue OLEDs and WOLEDs based on single component. Conjugation-blocking sp3 hybridized O and S atoms and ICT-enhancing cyano groups are adopted to construct two novel anthracene-based "hot exciton" materials, OPACN and SPACN. OLED based on OPACN shows blue emission with CIEy coordinate of 0.10 and maximum EQE of 8.7%. Furthermore, the single component WOLED based on OPACN exhibits maximum EQE of 5.4% and low efficiency roll-off. image