Abstract White organic light emitting diodes (WOLEDs) incorporating gold (Au) nanoparticles (NPs) beneath PEDOT:PSS hole injection layer (HIL) and employing neat blue DMAC-DPS(B) and green 4CzIPN(G) thermally activated delayed fluorescence (TADF) emission layer (EML) together with sandwiched ultrathin red phosphorescence Ir(piq)2(acac)(R) EML have been fabricated and the effects of the localized surface plasmon resonance (LSPR) of Au NPs and EML thickness on the electroluminescence (EL) performance are investigated. It is found that EML thickness imposes vital influence on the EL performance of the WOLEDs and the WOLEDs with the embedded Au NPs and simple EML structure with optimal thickness of G(15 nm)/R(0.3 nm)/B(15 nm) demonstrate maximum power efficiency (PE), external quantum efficiency (EQE) and color rendering index (CRI) around 11.73 lm/w, 10.51% and 94, indicating the achievement of balance between EL efficiency and CRI by carefully adjustment of EML thickness with the presence of Au NPs. Furthermore, the LSPR effects from the Au NPs on the EL efficiency and CRI have been clearly demonstrated. Especially the green and red light emission is dramatically enhanced leading to enormous improvement of CRI, which can be ascribed to the remarkable enhancement of energy transferring inside G(15 nm)/R(0.3 nm)/B(15 nm) EML proved by the much shortened decaying lifetime at 475 and 550 nm from transient photoluminescence(PL) decaying testing. Almost double enhancement of the total fluorescence efficiency (including prompt fluorescence (PF) and delayed fluorescence (DF)) at 550 nm can be obtained with the assistance of LSPR from Au NPs, which increase from 23.85% to 49.82% and 15.22%–28.86% for respective EML of G(15 nm)/B(15 nm) and G(15 nm)/R(0.3 nm)/B(15 nm). The decaying dynamics including the DF, PF, phosphorescence (PH) and energy transferring inside G(15 nm)/R(0.3 nm)/B(15 nm) EML with and without embedded Au NPs is discussed in details. The study provides an easy way to utilize the LSPR of Au NPs together with simple neat TADF and phosphorescent EML to develop high quality WOLEDs.

中文翻译：

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基于 Au 纳米粒子的局域表面等离子体共振和纯热激活延迟荧光和磷光发射层的白色有机发光二极管

摘要 白色有机发光二极管 (WOLED) 在 PEDOT:PSS 空穴注入层 (HIL) 下方加入金 (Au) 纳米粒子 (NP)，并采用纯蓝色 DMAC-DPS(B) 和绿色 4CzIPN(G) 热激活延迟荧光 (TADF) ) 发射层 (EML) 和夹心超薄红色磷光 Ir(piq)2(acac)(R) EML 已经制造，并且 Au NPs 的局域表面等离子体共振 (LSPR) 和 EML 厚度对电致发光 (EL) 的影响) 性能进行了调查。发现 EML 厚度对 WOLED 的 EL 性能产生重要影响，具有嵌入 Au NPs 和简单 EML 结构的 WOLED 具有最佳厚度 G(15 nm)/R(0.3 nm)/B(15 nm) 证明最大功率效率 (PE)、外量子效率 (EQE) 和显色指数 (CRI) 约为 11.73 lm/w，10.51% 和 94，表明通过在 Au NP 的存在下仔细调整 EML 厚度，实现了 EL 效率和 CRI 之间的平衡。此外，Au NPs 的 LSPR 对 EL 效率和 CRI 的影响已得到明确证明。特别是绿光和红光的发射显着增强，显着提高了显色性，这可以归因于 G(15 nm)/R(0.3 nm)/B(15 nm) EML 内部能量转移的显着增强，由从瞬态光致发光 (PL) 衰减测试中大大缩短了 475 和 550 nm 的衰减寿命。在 LSPR 的辅助下，Au NPs 的总荧光效率（包括瞬发荧光 (PF) 和延迟荧光 (DF)）在 550 nm 处几乎翻倍，从 23.85% 增加到 49.82% 和 15.22%–28 . G(15 nm)/B(15 nm) 和 G(15 nm)/R(0.3 nm)/B(15 nm) 的相应 EML 为 86%。详细讨论了衰减动力学，包括 DF、PF、磷光 (PH) 和 G(15 nm)/R(0.3 nm)/B(15 nm) EML 内的能量转移，有和没有嵌入的 Au NPs。该研究提供了一种简单的方法来利用 Au NPs 的 LSPR 以及简单的纯 TADF 和磷光 EML 来开发高质量的 WOLED。