Seo Ji Hyun, Lee Seok Jae, Kim Bo Young, Choi Eun Young, Han Wone Keun, Lee Kum Hee, Yoon Seung Soo, Kim Young Kwan
Department of Information Display, Hongik University, Seoul 121-791, Korea.
J Nanosci Nanotechnol. 2012 May;12(5):4190-3. doi: 10.1166/jnn.2012.5913.
We demonstrated that the simple layered red phosphorescent organic light-emitting diodes (OLEDs) are possible to have high efficiency, low driving voltage, stable roll-off efficiency, and pure emission color without hole injection and transport layers. We fabricated the OLEDs with a structure of ITO/CBP doped with Ir(pq)2(acac)/BPhen/Liq/Al, where the doping concentration of red dopant, Ir(pq)2(acac), was varied from 4% to 20%. As a result, the quantum efficiencies of 13.4, 11.2, 16.7, 10.8 and 9.8% were observed in devices with doping concentrations of 4, 8, 12, 16 and 20%, respectively. Despite of absence of the hole injection and transport layers, these efficiencies are superior to efficiencies of device with hole transporting layer due to direct hole injection from anode to dopant in emission layer.
我们证明了简单的层状红色磷光有机发光二极管（OLED）在没有空穴注入和传输层的情况下，有可能具有高效率、低驱动电压、稳定的滚降效率和纯发射颜色。我们制备了结构为ITO/CBP掺杂Ir(pq)2(acac)/BPhen/Liq/Al的OLED，其中红色掺杂剂Ir(pq)2(acac)的掺杂浓度从4%变化到20%。结果，在掺杂浓度分别为4%、8%、12%、16%和20%的器件中，观察到的量子效率分别为13.4%、11.2%、16.7%、10.8%和9.8%。尽管没有空穴注入和传输层，但由于空穴从阳极直接注入到发射层中的掺杂剂，这些效率优于有空穴传输层的器件的效率。
