Nb_2O_5空穴注入层的引入对OLEDs性能的影响

Improved Performances of Organic Light-emitting Diodes by Insertion of Nb_2O_5 as Hole Injection Layer

在有机发光二极管典型的层状结构中,引入磁控溅射制备Nb2O5超薄膜作空穴注入层,制备了结构为ITO/Nb2O5/TPD/Alq3/Al的器件。Nb2O5层的引入,降低了空穴注入势垒,增强了空穴注入,同时有效阻挡了ITO中In向有机层的扩散,减少了发光猝灭中心的形成,提高了器件的亮度和效率。研究了不同厚度Nb2O5层对器件光电性能的影响,发现:当引入Nb2O5层厚度为2nm时,亮度提高了近2倍,效率由3.5cd/A增加到了7.8cd/A,较好地改善了器件的性能,并且性能优于含有CuPc常规注入层的器件。

A novel hole injection layer using niobium oxide by RF magnetron sputtering in organic light-emitting diode has been fabricated. Performances of the diode have been improved greatly with structure of ITO/ Nb2O5/TPD/Alq3/Al （ TPD： N, N＇-iphenyl-N, N＇-bis （ 3-methylphenyl）-1, 1 ＇-biphenyl-4, 4＇-diamine,Alq3 ： tris（8-quinolinolato）-aluminum）. The insertion of this ultra-thin film results in a similar reduction of the hole injection barrier, which is related to the thickness of the film. That enhances the hole injection and improves the luminance and efficiency of the diode, since the inserted layer simultaneously blocks the diffusion of metal In into organic layers. The diode with a 2 nm Nb2O5 layer shows the best performance, having the largest luminance 2 560 cd/m^2 at 20 V and efficiency increases to 7.8 cd/A in comparison with 3.5 cd/A of the diode without Nb2O5 layer. And, it has been proved to be a good choice compared with CuPc, which is usually used as the injection layer.