Cibalackrot Dendrimers for Hyperfluorescent Organic Light‐Emitting Diodes
Cibalackrot Dendrimers for Hyperfluorescent Organic Light‐Emitting Diodes
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用于超荧光有机发光二极管的 Cibalackrot 树枝状聚合物
DOI：
10.1002/marc.202200118
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发表时间：
2022
影响因子：
4.6
通讯作者：
Lo Shih‐Chun
中科院分区：
文献类型：
--
作者：
Wallwork Nicholle R.;Mamada Masashi;Keto Angus B.;McGregor Sarah K. M.;Shukla Atul;Adachi Chihaya;Krenske Elizabeth H.;Namdas Ebinazar B.;Lo Shih‐Chun
超荧光有机发光二极管 (HF-OLED) 能够实现从合适的热激活延迟荧光 (TADF) 辅助主体到荧光末端发射器的级联福斯特共振能量转移 (FRET)，从而提供与 TADF-OLED 相比电致发光相对较窄的高效 OLED。高效的 HF-OLED 需要通过从 TADF 辅助主体到荧光末端发射器的 Dexter 型能量转移（DET）实现最佳的 FRET 和最小的三线态扩散。为了阻碍 DET，有人提出对末端发射器进行空间保护来破坏三重态能量转移。在这项工作中，报道了第一个基于结构明确的大分子、树枝状聚合物的 HF-OLED。该树枝状聚合物含有连接到 Cibalackrot 核心的新型高度扭曲树枝，从而在有机溶剂中具有高溶解度。基于树枝状聚合物共混薄膜的 HF-OLED 在 100 cd m−2 下表现出 >10% 的外部量子效率。重要的是，发现大树突的树突化对 FRET 效率没有负面影响，这表明树突状大分子基序在 HF-OLED 中具有巨大的潜力。为了完全防止不需要的三重态扩散，Cibalackrot 树枝状聚合物 HF-OLED 有望通过在 Cibalackrot 核心中添加额外的树枝和/或增加树枝状聚合物的代数来进一步改进。
Hyperfluorescent organic light‐emitting diodes (HF‐OLEDs) enable a cascading Förster resonance energy transfer (FRET) from a suitable thermally activated delayed fluorescent (TADF) assistant host to a fluorescent end‐emitter to give efficient OLEDs with relatively narrowed electroluminescence compared to TADF‐OLEDs. Efficient HF‐OLEDs require optimal FRET with minimum triplet diffusion via Dexter‐type energy transfer (DET) from the TADF assistant host to the fluorescent end‐emitter. To hinder DET, steric protection of the end‐emitters has been proposed to disrupt triplet energy transfer. In this work, the first HF‐OLEDs based on structurally well‐defined macromolecules, dendrimers is reported. The dendrimers contain new highly twisted dendrons attached to a Cibalackrot core, resulting in high solubility in organic solvents. HF‐OLEDs based on dendrimer blend films are fabricated to show external quantum efficiencies of >10% at 100 cd m−2. Importantly, dendronization with the bulky dendrons is found to have no negative impact to the FRET efficiency, indicating the excellent potential of the dendritic macromolecular motifs for HF‐OLEDs. To fully prevent the undesired triplet diffusion, Cibalackrot dendrimers HF‐OLEDs are expected to be further improved by adding additional dendrons to the Cibalackrot core and/or increasing dendrimer generations.