High-Performance Dibenzoheteraborin-Based Thermally Activated Delayed Fluorescence Emitters: Molecular Architectonics for Concurrently Achieving Narrowband Emission and Efficient Triplet-Singlet Spin Conversion
High-Performance Dibenzoheteraborin-Based Thermally Activated Delayed Fluorescence Emitters: Molecular Architectonics for Concurrently Achieving Narrowband Emission and Efficient Triplet-Singlet Spin Conversion
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DOI：
10.1002/adfm.201802031
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发表时间：
2018-08-22
影响因子：
19
通讯作者：
Yasuda, Takuma
中科院分区：
文献类型：
--
作者：
Park, In Seob;Matsuo, Kyohei;Yasuda, Takuma
热激活延迟荧光（TADF）材料能够完全捕获单重态和三重态激发态用于发光，有望取代传统的荧光和磷光材料，成为有机发光二极管（OLED）的第三代发光材料。高光致发光量子产率（phi（PL））、窄带发射（或高色纯度）和短延迟荧光寿命都是实际应用中强烈期望的。然而，到目前为止，没有合理的设计策略的TADF发射器建立满足这些要求。在这里，提出了一个划时代的设计策略，用于生产高性能的TADF发射器，同时表现出高的phi（PL）值接近100%，窄的发射带宽，和短的发射寿命约为1 μ s，与快速反向系统间穿越率超过10（6）s（-1）。介绍了一种新的基于二苯并杂硼杂环的TADF发射体家族，其使得掺杂和非掺杂的TADF-OLED都能够实现显著高的外部电致发光量子效率，超过20%，并且在实际高亮度下的效率滚降可以忽略不计。本文报道了这些基于二苯并杂硼啉的TADF发射体的系统的物理和理论研究以及器件评价。
Thermally activated delayed fluorescence (TADF) materials, which enable the full harvesting of singlet and triplet excited states for light emission, are expected as the third-generation emitters for organic light-emitting diodes (OLEDs), superseding the conventional fluorescence and phosphorescence materials. High photoluminescence quantum yield (phi(PL)), narrow-band emission (or high color purity), and short delayed fluorescence lifetime are all strongly desired for practical applications. However, to date, no rational design strategy of TADF emitters is established to fulfill these requirements. Here, an epoch-making design strategy is proposed for producing high-performance TADF emitters that concurrently exhibiting high phi(PL) values close to 100%, narrow emission bandwidths, and short emission lifetimes of approximate to 1 mu s, with a fast reverse intersystem crossing rate of over 10(6) s(-1). A new family of TADF emitters based on dibenzoheteraborins is introduced, which enable both doped and non-doped TADF-OLEDs to achieve markedly high external electroluminescence quantum efficiencies, exceeding 20%, and negligible efficiency roll-offs at a practical high luminance. Systematic photophysical and theoretical investigations and device evaluations for these dibenzoheteraborin-based TADF emitters are reported here.