Electron injection into hole-transporting layer from emission layer in organic light emitting diodes
Electron injection into hole-transporting layer from emission layer in organic light emitting diodes
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有机发光二极管中电子从发射层注入空穴传输层
DOI：
10.1002/pssc.201084048
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
他4名
中科院分区：
文献类型：
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作者：
T. Tsuboi;他4名
研究了以N，N′-二（萘-1-基）-N，N′-二苯基联苯胺（NPB）为发光层，分别掺杂0.2，0.5，1.0%三[1-苯基异喹啉-C2，N]铱[Ir（piq）3]的有机电致发光器件的光电特性。分别使用三（8-羟基喹啉）铝（Alq 3）和NPB作为电子和空穴传输层。在所有器件中均观察到Ir（piq）3掺杂和Alq 3的发射。即使在掺杂浓度为0.2%的器件中也没有观察到来自NPB宿主的发射。这通过NPB和Alq 3之间的高HOMO能隙（0.8eV）以及Ir（piq）3和Alq 3之间的非常小的HOMO能隙（0.1eV）来理解，这不会导致电子从Alq 3电子传输层注入到发光层中的NPB主体中，而是导致电子从Alq 3直接注入到Ir（piq）3中。结果表明，随着掺杂浓度的增加，器件的驱动电压、外量子效率和发光效率增加，而功率效率降低。（© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA，魏因海姆）
Optical and electrical characteristics of organic light emitting diode devices with emitting layer of N,N′‐di(naphthalene‐1‐yl)‐N,N′‐diphenyl‐benzidine (NPB) doped with 0.2, 0.5, and 1.0% tris[1‐phenylisoquinolinato‐C2, N] iridium [Ir(piq)3] are presented. Tris(8‐hydroxyquinoline) aluminum (Alq3) and NPB were used as electron and hole transport layers, respectively. Emissions from Ir(piq)3dopant and Alq3have been observed in all the devices. No emission from NPB host was observed even in device with 0.2% dopant concentration. This is understood by the high HOMO gap (0.8 eV) between NPB and Alq3and by the very small HOMO gap (0.1 eV) between Ir(piq)3and Alq3, which do not lead to injection of electrons from Alq3electron transport layer into NPB host in emitting layer but lead to direct injection of electrons from Alq3into Ir(piq)3. It was found that the driving voltage, external quantum efficiency, and luminous efficiency increase with increasing dopant concentration, but power efficiency decrease. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)