AUTHOR=Gawale Yogesh , Ansari Rasheeda , Naveen Kenkera Rayappa , Kwon Jang Hyuk 

TITLE=Forthcoming hyperfluorescence display technology: relevant factors to achieve high-performance stable organic light emitting diodes

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 11 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2023.1211345

DOI=10.3389/fchem.2023.1211345

ISSN=2296-2646

ABSTRACT=Over the decade, there have been developments in purely organic thermally activated delayed fluorescent (TADF) materials for organic light-emitting diodes (OLEDs). However, achieving narrow full width at half maximum (FWHM) and high external quantum efficiency (EQE) is crucial for real display industries. To overcome these hurdles, hyperfluorescence (HF) technology was proposed for next-generation OLEDs. In this technology, the TADF material was considered as a sensitizing host, the so-called TADF sensitized host (TSH), for the use of triplet excitons via reverse intersystem crossing (RISC) pathway. Since most TADF materials show bipolar characteristics, electrically generated singlet and triplet exciton energies can be conveyed to the final fluorescent emitter through Förster resonance energy transfer (FRET) rather than Dexter energy transfer (DET). This mechanism is possible from the S1 state of TSH to the S1 state of the final fluorescent dopant (FD) as a long-range energy transfer. Considering this, some reports are available based on HF OLEDs, but the detailed analysis for highly efficient and stable devices for commercialization was unclear. So herein, we reviewed the relevant factors based on recent advancements to build a highly efficient and stable HF system. The factors include energy transfer mechanism based on spectral overlapping, TSH requirements, electroluminescence study based on exciplex and polarity system, shielding effect, DET suppression, and FD orientation. Further, the outlook and future positives with new directions were discussed to build high-performance OLEDs.