有机发光二极管
量子效率
共发射极
材料科学
光电子学
电致发光
量子产额
光致发光
二极管
波长
荧光
光学
纳米技术
物理
图层(电子)
作者
Yuan‐Lan Zhang,Quan Ran,Qiang Wang,Yuan Liu,Christian Hänisch,Sebastian Reineke,Jian Fan,Liang‐Sheng Liao
标识
DOI:10.1002/adma.201902368
摘要
Abstract Researchers have spared no effort to design new thermally activated delayed fluorescence (TADF) emitters for high‐efficiency organic light‐emitting diodes (OLEDs). However, efficient long‐wavelength TADF emitters are rarely reported. Herein, a red TADF emitter, TPA–PZCN, is reported, which possesses a high photoluminescence quantum yield ( Φ PL ) of 97% and a small singlet–triplet splitting (Δ E ST ) of 0.13 eV. Based on the superior properties of TPA–PZCN, red, deep‐red, and near‐infrared (NIR) OLEDs are fabricated by utilizing different device structure strategies. The red devices obtain a remarkable maximum external quantum efficiency (EQE) of 27.4% and an electroluminescence (EL) peak at 628 nm with Commission Internationale de L'Eclairage (CIE) coordinates of (0.65, 0.35), which represents the best result with a peak wavelength longer than 600 nm among those of the reported red TADF devices. Furthermore, an exciplex‐forming cohost strategy is adopted. The devices achieve a record EQE of 28.1% and a deep‐red EL peak at 648 nm with the CIE coordinates of (0.66, 0.34). Last, nondoped devices exhibit 5.3% EQE and an NIR EL peak at 680 nm with the CIE coordinates of (0.69, 0.30).
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