Park Jeong Yong, Kwak Seon Lee, Park Hea Jung, Hwang Do-Hoon
Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan 46241, Republic of Korea.
Department of Biology and Chemistry, Changwon National University, Changwon 51140, Republic of Korea.
Nanomaterials (Basel). 2023 Jun 25;13(13):1934. doi: 10.3390/nano13131934.
We designed and synthesized a new indolocarbazole-based polymer, poly(N,N-diphenyl(5,11-dihexylindolo[3,2,1-jk]carbazol-2-yl)amine) (PICA), for solution-processed organic light-emitting diodes (OLEDs). The highest occupied and lowest unoccupied molecular orbital energy levels of this polymer, -5.25 and -2.46 eV, respectively, are suitable for hole transport from the anode to the emissive layer. PICA was photo-crosslinked by UV irradiation with ethane-1,2-diyl bis(4-azido-2,3,5,6-tetrafluorobenzoate) (FPA) as the photoinitiator. Successful crosslinking was confirmed by a decreased intensity in the azide-stretching FT-IR peak and solvent test with toluene (a suitable solvent for PICA). The PICA film photo-crosslinked with 3 wt% FPA showed enhanced solvent resistance (90%) compared to the non-crosslinked neat PICA film (<20%). Moreover, OLED devices using PICA-based hole-transporting layers exhibited better device performance (EQE/LE/PE: 8.88%/12.97/8.12 in red devices, 10.84%/38.47 cd/A/25.06 lm/W in green devices) than those using poly-TPD:FPA. We demonstrated that the photo-crosslinked PICA can be applied as a hole-transporting layer in solution-processed OLEDs.
我们设计并合成了一种新型的基于吲哚并咔唑的聚合物，聚（N，N - 二苯基（5,11 - 二己基吲哚并[3,2,1 - jk]咔唑 - 2 - 基）胺）（PICA），用于溶液处理的有机发光二极管（OLED）。该聚合物的最高占据分子轨道和最低未占据分子轨道能级分别为 -5.25和 -2.46 eV，适合空穴从阳极传输到发光层。PICA通过以乙烷 - 1,2 - 二基双（4 - 叠氮基 - 2,3,5,6 - 四氟苯甲酸酯）（FPA）作为光引发剂的紫外线照射进行光交联。通过叠氮拉伸傅里叶变换红外光谱峰强度降低和用甲苯（PICA的合适溶剂）进行的溶剂测试证实了成功交联。与未交联的纯PICA膜（<20%）相比，用3 wt% FPA光交联的PICA膜表现出增强的耐溶剂性（90%）。此外，使用基于PICA的空穴传输层的OLED器件比使用聚 - TPD:FPA的器件表现出更好的器件性能（红色器件的EQE/LE/PE：8.88%/12.97/8.12，绿色器件的10.84%/38.47 cd/A/25.06 lm/W）。我们证明了光交联的PICA可作为溶液处理的OLED中的空穴传输层应用。
