Enhancement of Forster energy transfer from thermally activated delayed fluorophores layer to ultrathin phosphor layer for high color stability in non-doped hybrid white organic light-emitting devices
Enhancement of Forster energy transfer from thermally activated delayed fluorophores layer to ultrathin phosphor layer for high color stability in non-doped hybrid white organic light-emitting devices
复制标题
增强从热激活延迟荧光团层到超薄荧光粉层的福斯特能量转移，以实现非掺杂混合白色有机发光器件的高颜色稳定性
DOI：
10.1088/1674-1056/26/4/047302
复制
发表时间：
2017
影响因子：
1.7
通讯作者：
Yu Junsheng
中科院分区：
文献类型：
--
作者：
Wang Zijun;Zhao Juan;Zhou Chang;Qi Yige;Yu Junsheng
制备了具有高颜色稳定性的基于双发光层的荧光/磷光混合白色有机电致发光器件。简化的EML由使用9，9-二甲基-9，10-二氢吖啶-二苯砜（DMAC-DPS）的非掺杂蓝色热激活延迟荧光（TADF）层和使用双[2-（4-叔丁基苯基）苯并噻唑-N，C2 ']铱（乙酰丙酮）（（tbt）2 Ir（acac））的非掺杂黄色磷光层组成。选择4，7-二苯基-1，10-菲咯啉（Bphen）和1，3，5-三（2-N-苯基苯并咪唑基）苯（TPBi）两种材料作为电子传输层（ETL），并通过调整黄色EML的厚度来优化器件性能。基于0.3 nm厚的黄色EML和Bphen的器件在52 cd/m2至6998 cd/m2的亮度范围内表现出高的颜色稳定性，具有轻微的国际照明委员会（CIE）坐标变化（0.017，0.009）。基于TPBi的器件产生高效率，最大外量子效率（EQE）、电流效率和功率效率分别为10%、21.1 cd/A和21.3 lm/W。黄色EML抑制空穴俘获和短半径Dexter能量转移，因此从DMAC-DPS到（tbt）2 Ir（acac）的Förster能量转移（FRET）占主导地位，这有利于保持颜色稳定。采用具有较高三重态激发态的TPBi有效地消除了ETL对三重态激子的猝灭，从而提高了器件效率。
Fluorescence/phosphorescence hybrid white organic light-emitting devices (WOLEDs) based on double emitting layers (EMLs) with high color stability are fabricated. The simplified EMLs consist of a non-doped blue thermally activated delayed fluorescence (TADF) layer using 9,9-dimethyl-9,10-dihydroacridine-diphenylsulfone (DMAC-DPS) and an ultrathin non-doped yellow phosphorescence layer employing bis[2-(4-tertbutylphenyl)benzothiazolato-N, C2’] iridium (acetylacetonate) ((tbt)2Ir(acac)). Two kinds of materials of 4,7-diphenyl-1,10-phenanthroline (Bphen) and 1,3,5-tris(2-N-phenylbenzimidazolyl) benzene (TPBi) are selected as the electron transporting layer (ETL), and the thickness of yellow EML is adjusted to optimize device performance. The device based on a 0.3-nm-thick yellow EML and Bphen exhibits high color stability with a slight Commission International de l’Eclairage (CIE) coordinates variation of (0.017, 0.009) at a luminance ranging from 52 cd/m2 to 6998 cd/m2. The TPBi-based device yields a high efficiency with a maximum external quantum efficiency (EQE), current efficiency, and power efficiency of 10%, 21.1 cd/A, and 21.3 lm/W, respectively. The ultrathin yellow EML suppresses hole trapping and short-radius Dexter energy transfer, so that Förster energy transfer (FRET) from DMAC-DPS to (tbt)2Ir(acac) is dominant, which is beneficial to keep the color stable. The employment of TPBi with higher triplet excited state effectively alleviates the triplet exciton quenching by ETL to improve device efficiency.