Bipyridine-Containing Host Materials for High Performance Yellow Thermally Activated Delayed Fluorescence-Based Organic Light Emitting Diodes with Very Low Efficiency Roll-Off
Bipyridine-Containing Host Materials for High Performance Yellow Thermally Activated Delayed Fluorescence-Based Organic Light Emitting Diodes with Very Low Efficiency Roll-Off
复制标题
DOI：
10.1002/adom.201901283
复制
发表时间：
2019-11-21
影响因子：
9
通讯作者：
Zysman-Colman, Eli
中科院分区：
文献类型：
--
作者：
Chen, Dongyang;Rajamalli, Pachaiyappan;Zysman-Colman, Eli
报道了两种双极基质材料3-CBPy和4-mCBPy。这些主体是常见主体材料CBP和mCBP的结构类似物，其中苯环已被吡啶取代。这两种材料具有较深的最高占据分子轨道(HOMO)和较浅的最低未占据分子轨道(LUMO)能级，以及足够高的能级S-1和T-1，这使得它们适合作为电致发光器件中黄色发光体的基质。以2，4，6-Tris(4-(10H-phenoxazin-10-yl)phenyl)-1，3，5-triazine(Tri-Pxz-Trz)为掺杂剂，以3-CBPy或4-mCBPy为基质制备了黄色发光延迟荧光有机电致发光二极管。将它们的器件性能与使用CBP和mCBP作为主体材料的类似器件进行了比较。含有吡啶的主体器件表现出明显的外量子效率(EQE)和减少滚降。7wt%tri-PXZ-TRZ掺杂器件具有很低的开启电压(3-CBPy和4-mCBPy均为2.5V)，最大外量子效率(EQE(Max))分别达到15.6%(3-CBPy)和19.4%(4-mCBPy)。使用4-mCBPy的器件也表现出很低的效率滚降，在10000cdm(-2)的亮度下，EQE为16.0%。
Two bipolar host materials 3-CBPy and 4-mCBPy are reported. These hosts are structural analogs of the common host materials CBP and mCBP wherein the phenyl rings have been replaced with pyridines. The two materials possess deep highest occupied molecular orbital (HOMO) and shallow lowest unoccupied molecular orbital (LUMO) levels along with sufficiently high energy S-1 and T-1 states that make them suitable hosts for yellow emitters in electroluminescent devices. Yellow-emitting thermally activated delayed fluorescence organic light-emitting diodes are fabricated using 2,4,6-tris (4-(10H-phenoxazin-10-yl)phenyl)-1,3,5-triazine (tri-PXZ-TRZ) as the dopant emitter with either 3-CBPy or 4-mCBPy employed as the host. Their device performance is compared to analogous devices using CBP and mCBP as host materials. The pyridine-containing host devices show markedly improved external quantum efficiencies (EQE) and decreased roll-off. The 7 wt% tri-PXZ-TRZ-doped device exhibits very low turn-on voltage (2.5 V for both 3-CBPy and 4-mCBPy) along with maximum external quantum efficiencies (EQE(max)) reaching 15.6% (for 3-CBPy) and 19.4% (for 4-mCBPy). The device using 4-mCBPy also exhibits very low efficiency roll-off with an EQE of 16.0% at a luminance of 10 000 cd m(-2).