Built-in field electroabsorption spectroscopy of polymer light-emitting diodes incorporating a doped poly(3,4-ethylene dioxythiophene) hole injection layer
Built-in field electroabsorption spectroscopy of polymer light-emitting diodes incorporating a doped poly(3,4-ethylene dioxythiophene) hole injection layer
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DOI：
10.1063/1.124789
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发表时间：
1999-09-20
影响因子：
4
通讯作者：
Feast, WJ
中科院分区：
文献类型：
--
作者：
Brown, TM;Kim, JS;Feast, WJ
报道了以聚(4-4‘-二苯基二苯乙撑)、PDPV为发光层、Ca-Al为阴极、氧化铟锡(ITO)为阳极的聚合物电致发光二极管(LED)的电吸收测量，在有或没有掺杂导电聚合物空穴注入/传输层的情况下，即聚(3，4-乙二氧基噻吩烯)，PEDOT，掺杂聚苯磺酸，PSS-。在这些结构中，电吸收信号为零的偏置对应于电极功函数之间的差。我们发现，当在ITO电极和发射层之间加入PEDOT：PSS薄膜时，这样的内置电压增加了0.5V。这导致空穴注入界面的阳极势垒高度显著降低，并解释了PEDOT插入带来的各种改善，即：(A)发光效率的提高，(B)开启电压的降低，以及(C)器件寿命的延长。(C)1999年美国物理研究所。[S0003-6951(99)04138-8]。
We report electroabsorption measurements of polymer light-emitting diodes, (LEDs), fabricated with poly(4-4(')-diphenylene diphenylvinylene), PDPV, as the emissive layer, Ca-Al cathodes, and indium tin oxide (ITO) anodes, with and without a doped conducting polymer hole injection/transport layer, namely poly(3,4-ethylene dioxythiophene), PEDOT, doped with poly(styrene sulfonate), PSS-. In these structures, the bias at which the electroabsorption signal is null corresponds to the difference between the electrodes' work functions. We find that such a built-in voltage increases by 0.5 V when a PEDOT:PSS film is incorporated between the ITO electrode and the emissive layer. This leads to a marked reduction of the anode barrier height at the hole-injecting interface, and accounts for a variety of improvements brought about by the PEDOT insertion, namely: (a) the increase of luminescence efficiency, (b) the reduction of the turn-on voltage, and (c) the increase of the device lifetime. (C) 1999 American Institute of Physics. [S0003-6951(99)04138-8].