High-performance crystalline organic light-emitting diodes based on multi-layer high-quality crystals.

Abstract Crystalline organic light-emitting diodes (OLEDs) are of great potential for the applications in solid-state lighting and electrically pumped organic lasers. Now the performance of crystalline OLEDs is poor because those devices typically use a single organic material with unmatched electron and hole mobilities resulting in imbalance charge injection. Here, we fabricate a crystalline OLED with a multi-layer architecture based on high-quality crystalline films. The device exhibits low driving voltage and high efficiency due to balanced charge injection and exciton confinement. An external quantum efficiency (EQE) of 2.41% is achieved, and the EQE value is the highest efficiency in the field of crystalline OLEDs to date. We expect that our results will be a starting point for further research, providing high-performance crystalline OLEDs for solid-state lighting and electrically pumped organic lasers. Graphical abstract Image 1 Highlights • High-quality multi-layer crystalline films were prepared. • The multi-layer crystalline OLED features balanced charge injection and exciton limitation. • The multi-layer crystalline OLED exhibits low driving voltage and high efficiency. [ABSTRACT FROM AUTHOR]