Emerging hyperfluorescent emitters for solid-state lighting

Organic light-emitting diodes (OLEDs) are of high interest for display, biomedical, and solid-state lighting applications. But costs and color purity are still issues with OLED technology. The development of triplet harvesting emitters with a thermally activated delayed fluorescence (TADF) mechanism mends these problems to some extent, owing to their ability to produce both singlet and triplet excitons. In addition, the recent development of hyperfluorescent OLEDs (HF-OLED) based on TADF and fluorescence emitter couples have attracted a lot of attention, realizing high efficiency, good stability, and narrow emission. In this mini-review, we comprehensively documented the molecular design principles of hyperfluorescence emitters, their fundamental photophysics, and the advances in their applications in OLEDs. Finally, the future perspectives of hyperfluorescence emitters and OLEDs are envisaged.