Deori Upasana, Nanda Gyana Prakash, Murawski Caroline, Rajamalli Pachaiyappan
Materials Research Centre, Indian Institute of Science Bangalore 560012 Karnataka India
Kurt-Schwabe-Institut für Mess- und Sensortechnik Meinsberg e.V. Kurt-Schwabe-Straße 4 04736 Waldheim Germany.
Chem Sci. 2024 Oct 8;15(43):17739-59. doi: 10.1039/d4sc05489j.
Hyperfluorescence, also known as thermally activated delayed fluorescence (TADF) sensitized fluorescence, is known as a next-generation efficient and innovative process for high-performance organic light-emitting diodes (OLEDs). High external quantum efficiency (EQE) and good color purity are crucial parameters for display applications. Hyperfluorescent OLEDs (HF-OLEDs) take the lead in this respect as they utilize the advantages of both TADF emitters and fluorescent dopants, realizing high EQE with color saturation and long-term stability. Hyperfluorescence is mediated through Förster resonance energy transfer (FRET) from a TADF sensitizer to the final fluorescent emitter. However, competing loss mechanisms such as Dexter energy transfer (DET) of triplet excitons and direct charge trapping on the final emitter need to be mitigated in order to achieve fluorescence emission with high efficiency. Despite tremendous progress, appropriate guidelines and fine optimization are still required to address these loss channels and to improve the device operational lifetime. This perspective aims to provide an overview of the evolution of HF-OLEDs by reviewing both molecular and device design pathways for highly efficient narrowband devices covering all colors of the visible spectrum. Existing challenges and potential solutions, such as molecules with peripheral inert substitution, multi-resonant (MR) TADF emitters as final dopants, and exciplex-sensitized HF-OLEDs, are discussed. Furthermore, the operational device lifetime is reviewed in detail before concluding with suggestions for future device development.
超荧光，也称为热激活延迟荧光（TADF）敏化荧光，是高性能有机发光二极管（OLED）的一种下一代高效创新工艺。高外量子效率（EQE）和良好的色纯度是显示应用的关键参数。超荧光OLED（HF - OLED）在这方面领先，因为它们利用了TADF发光体和荧光掺杂剂的优势，实现了具有色彩饱和度和长期稳定性的高EQE。超荧光是通过从TADF敏化剂到最终荧光发射体的福斯特共振能量转移（FRET）介导的。然而，为了实现高效的荧光发射，需要减轻诸如三重态激子的德克斯特能量转移（DET）和最终发射体上的直接电荷俘获等竞争损耗机制。尽管取得了巨大进展，但仍需要适当的指导方针和精细优化来解决这些损耗通道并提高器件的工作寿命。这篇综述旨在通过回顾覆盖可见光谱所有颜色的高效窄带器件的分子和器件设计途径，概述HF - OLED的发展历程。讨论了现有挑战和潜在解决方案，例如具有外围惰性取代的分子、作为最终掺杂剂的多共振（MR）TADF发光体以及激基复合物敏化的HF - OLED。此外，在对未来器件发展提出建议之前，详细回顾了器件的工作寿命。
