N掺杂改善黄色磷光有机电致发光器件的效率滚降
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摘要
制备结构为ITO/HAT-CN/TAPC/TCTA/POAPF\:PO-01/Bphen/LiF/Al的黄色磷光器件,其效率滚降特性符合三重态-极化子淬灭模型;接着设计了一组单电子和单空穴器件,实验结果表明:发光层内的空穴是多子且PO-01俘获空穴,被PO-01俘获的多余空穴引起的激子淬灭是导致器件在高电流密度下效率剧烈滚降的原因;采用N掺杂的方法增加电子注入,可减少发光区内多余的空穴,改善器件载流子的平衡状况,降低多余空穴引起的激子淬灭,进而改善效率滚降。
Yellow phosphorescent organic light-emitting device is prepared, and the structure of the device is ITO/HAT-CN/TAPC/TCTA/POAPF\:PO-01/Bphen/LiF/Al. The efficiency roll-off of the device fits the triplet-polaron quenching model well. Then, electron-only and hole-only devices are designed. Experimental results show that the holes are majority carriers in light-emitting layer and PO-01 traps holes. The efficiency of the device rolls off drastically due to excitons quenching caused by PO-01 trapping excess holes at high current density. The method of N-doping is used to increase the electron injection, which reduces excess holes in the light-emitting region, improves the carriers balance of the device, and alleviates the excitons quenching caused by excess holes, thereby improving the efficiency roll-off.
Yellow phosphorescent organic light-emitting device is prepared, and the structure of the device is ITO/HAT-CN/TAPC/TCTA/POAPF\:PO-01/Bphen/LiF/Al. The efficiency roll-off of the device fits the triplet-polaron quenching model well. Then, electron-only and hole-only devices are designed. Experimental results show that the holes are majority carriers in light-emitting layer and PO-01 traps holes. The efficiency of the device rolls off drastically due to excitons quenching caused by PO-01 trapping excess holes at high current density. The method of N-doping is used to increase the electron injection, which reduces excess holes in the light-emitting region, improves the carriers balance of the device, and alleviates the excitons quenching caused by excess holes, thereby improving the efficiency roll-off.
引文
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[13] Wei X F, Tan W Y, Zou J H, et al. High Tg small-molecule phenanthroline derivatives as a potential universal hole-blocking layer for high power-efficiency and stable organic light-emitting diodes[J]. Journal of Materials Chemistry C, 2017, 5(9): 2329-2336.
[14] Wang F F, Tao Y T, Huang W. Recent progress of host materials for highly efficient blue phosphorescent OLEDs[J]. Acta Chimica Sinica, 2015, 73(1): 9-22. 王芳芳, 陶友田, 黄维. 高效蓝光有机电致磷光主体材料的研究进展[J]. 化学学报, 2015, 73(1): 9-22.
[15] Cheng Y J, Yu S Y, Lin S C, et al. A phenothiazine/dimesitylborane hybrid material as a bipolar transport host of red phosphor[J]. Journal of Materials Chemistry C, 2016, 4(40): 9499-9508.
[16] Wang X, Yu J S, Zhao J, et al. Comparison of electron transporting layer in white OLED with a double emissive layer structure[J]. Displays, 2012, 33(4/5): 191-194.
[17] Ma Y Z, Chung Y H , Zheng L L, et al. Improved hole-transporting property via HAT-CN for perovskite solar cells without lithium salts[J]. ACS Applied Materials & Interfaces, 2015, 7(12): 6406-6411.
[18] Xue K W, Han G G, Duan Y, et al. Doping-free orange and white phosphorescent organic light-emitting diodes with ultra-simply structure and excellent color stability[J]. Organic Electronics, 2015, 18: 84-88.
[2] Chen W B, Ma H, Ye J X, et al. Research progress on quantum dot light emitting diodes[J]. Laser & Optoelectronics Progress, 2017, 54(11): 110003. 陈雯柏, 马航, 叶继兴, 等. 量子点发光二极管的研究进展[J]. 激光与光电子学进展, 2017, 54(11): 110003.
[3] Furukawa T, Nakanotani H, Inoue M, et al. Dual enhancement of electroluminescence efficiency and operational stability by rapid upconversion of triplet excitons in OLEDs[J]. Scientific Reports, 2015, 5: 8429.
[4] Yang H S. Fabrications of white organic light-emitting device based on fluorescent sub-monolayer combine with phosphorescent doping layer[J]. Acta Optica Sinica, 2013, 33(3): 0323005. 杨惠山. 荧光亚单层结合磷光掺杂层制备白色有机发光器件[J]. 光学学报, 2013, 33(3): 0323005.
[5] Xiang C Y, Fu X Y, Wei W, et al. Efficiency roll-off in blue emitting phosphorescent organic light emitting diodes with carbazole host materials[J]. Advanced Functional Materials, 2016, 26(9): 1463-1469.
[6] Baldo M A, Adachi C, Forrest S R. Transient analysis of organic electrophosphorescence. II. Transient analysis of triplet-triplet annihilation[J]. Physical Review B, 2000, 62(16): 10967.
[7] Reineke S, Walzer K, Leo K. Triplet-exciton quenching in organic phosphorescent light-emitting diodes with Ir-based emitters[J]. Physical Review B, 2007, 75(12): 125328.
[8] Wu Z G, Zheng Y X, Zhou L, et al. Suppression of efficiency roll-off in highly efficient blue phosphorescent organic light-emitting devices using novel iridium phosphors with good electron mobility[J]. Organic Electronics, 2017, 42: 141-145.
[9] Yoo S I, Yoon J A, Kim N H, et al. Improvement of efficiency roll-off in blue phosphorescence OLED using double dopants emissive layer[J]. Journal of Luminescence, 2015, 160: 346-350.
[10] Kimura H. Semiconductor device and manufacturing method of the same: US9041202[P]. 2015-05-26.
[11] Yin X J, Zhang T K, Peng Q M, et al. Benzobisoxazole-based electron transporting materials with high Tg and ambipolar property: high efficiency deep-red phosphorescent OLEDs[J]. Journal of Materials Chemistry C, 2015, 3(29): 7589-7596.
[12] Wang J X, Chen J S, Qiao X F, et al. Simple-structured phosphorescent warm white organic light-emitting diodes with high power efficiency and low efficiency roll-off[J]. ACS Applied Materials & Interfaces, 2016, 8(16): 10093-10097.
[13] Wei X F, Tan W Y, Zou J H, et al. High Tg small-molecule phenanthroline derivatives as a potential universal hole-blocking layer for high power-efficiency and stable organic light-emitting diodes[J]. Journal of Materials Chemistry C, 2017, 5(9): 2329-2336.
[14] Wang F F, Tao Y T, Huang W. Recent progress of host materials for highly efficient blue phosphorescent OLEDs[J]. Acta Chimica Sinica, 2015, 73(1): 9-22. 王芳芳, 陶友田, 黄维. 高效蓝光有机电致磷光主体材料的研究进展[J]. 化学学报, 2015, 73(1): 9-22.
[15] Cheng Y J, Yu S Y, Lin S C, et al. A phenothiazine/dimesitylborane hybrid material as a bipolar transport host of red phosphor[J]. Journal of Materials Chemistry C, 2016, 4(40): 9499-9508.
[16] Wang X, Yu J S, Zhao J, et al. Comparison of electron transporting layer in white OLED with a double emissive layer structure[J]. Displays, 2012, 33(4/5): 191-194.
[17] Ma Y Z, Chung Y H , Zheng L L, et al. Improved hole-transporting property via HAT-CN for perovskite solar cells without lithium salts[J]. ACS Applied Materials & Interfaces, 2015, 7(12): 6406-6411.
[18] Xue K W, Han G G, Duan Y, et al. Doping-free orange and white phosphorescent organic light-emitting diodes with ultra-simply structure and excellent color stability[J]. Organic Electronics, 2015, 18: 84-88.