High-Efficiency Narrow-Band Electro-Fluorescent Devices with Thermally Activated Delayed Fluorescence Sensitizers Combined Through-Bond and Through-Space Charge Transfers,CCS Chemistry

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High-Efficiency Narrow-Band Electro-Fluorescent Devices with Thermally Activated Delayed Fluorescence Sensitizers Combined Through-Bond and Through-Space Charge Transfers
CCS Chemistry ( IF 9.4 ) Pub Date : 2020/8/11 , DOI: 10.31635/ccschem.020.202000243
Chen Yin ₁ , Dongdong Zhang ₁ , Yuewei Zhang ₁ , Yang Lu ₁ , Rui Wang ₁ , Guomeng Li ₁ , Lian Duan _{1,

2}

Affiliation

Organic light-emitting diodes utilizing thermally activated delayed fluorescence sensitizers and multiple-resonance (MR) dopants may simultaneously offer high efficiencies and narrow-band emissions, but these devices still face intractable challenges with a lack of design rules for high-performance sensitizers. Here, sensitizers with ortho-arranged donor–acceptors on a (trifluoromethyl)benzene linker have been proposed, which not only facilitate relatively small molecular dipole moments but also combine through-bond and through-space charge transfers for fast reverse intersystem crossing (RISC). Their photophysical properties are further modulated by additional electron-deficient moieties to better understand the interplay between sensitizer and MR dopant. The highest maximum external quantum efficiency of 33.1% together with a full width at half maximum of 28 nm were obtained in the device utilizing the sensitizer featuring the fastest RISC though inferior emission spectra overlap (J) with MR-dopant absorption among all sensitizers. It has been shown that, other than a blue-shifted emission to enhance J, an ideal sensitizer should establish efficient photoluminescence and fast RISC to suppress exciton loss and annihilation, as well as a small dipole moment to maintain the narrow-band emission of the MR dopant. These findings pave the way for practical applications of all fluorescent devices with both high efficiency and high color purity.

中文翻译：

高效率的窄带电致发光器件，具有热激活的延迟荧光增感剂，结合了通过键和通过空间的电荷转移

利用热激活的延迟荧光敏化剂和多共振（MR）掺杂剂的有机发光二极管可以同时提供高效率和窄带发射，但是由于缺少针对高性能敏化剂的设计规则，这些设备仍然面临棘手的挑战。在这里，已经提出了在（三氟甲基）苯连接基上带有邻位供体受体的敏化剂，它不仅可以促进相对较小的分子偶极矩，而且可以通过键合和空间电荷转移来实现快速反向系统间穿越（RISC）。它们的光物理性质被其他电子不足的部分进一步调节，以更好地理解敏化剂和MR掺杂剂之间的相互作用。最大外部量子效率最高为33。使用具有最快RISC的增感剂的设备在装置中获得了1％的半峰全宽和28 nm的半峰宽，尽管在所有增感剂中，较差的发射光谱重叠（J）且MR掺杂吸收。已经证明，除了蓝移发射以增强J之外，理想的敏化剂还应建立有效的光致发光和快速RISC来抑制激子损失和an灭，以及一个小的偶极矩来维持光子的窄带发射。 MR掺杂剂。这些发现为高效和高色纯度的所有荧光设备的实际应用铺平了道路。除了增加J的蓝移发射之外，理想的敏化剂还应建立有效的光致发光和快速RISC，以抑制激子损失和an灭，并具有较小的偶极矩，以保持MR掺杂剂的窄带发射。这些发现为高效和高色纯度的所有荧光设备的实际应用铺平了道路。除了增加J的蓝移发射之外，理想的敏化剂还应建立有效的光致发光和快速RISC，以抑制激子损失和an灭，并具有较小的偶极矩，以保持MR掺杂剂的窄带发射。这些发现为高效和高色纯度的所有荧光设备的实际应用铺平了道路。

更新日期：2020-09-16

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