有机白光器件中CdS薄层增加电子注入的研究

Research on Increasing Electron Injection in CdS Thin Layer of White Organic Light-emitting

为了研究光电材料CdS在有机白光器件中增加电子注入的特性,将结构为ITO/NPB/Rubrene/NPB/DPVBi/Alq3/LiF/Al的白光器件,不插入CdS薄层或将CdS薄层分别插入到NPB和ITO之间以及Alq3和LiF之间或同时将CdS薄层插入到它们之间,制作了四个元器件。通过研究得出,在Alq3和LiF之间插入CdS薄层的器件,在同等条件下性能较好。性能的改善来自于CdS薄层的引入使器件电子注入增加,激子形成的数量和比率也获得了相应的提高,从而提高了器件的亮度和效率。

In order to study the photoelectric characteristics of increasing the electron injection, white organic light-emitting diodes with the structure of ITO/NPB/Rubrene/NPB/ DPVBi/Alq3/LiF/Al were fabricated. Four devices with different inserting layer were fabricated as： for the first one, there is no insert of photoelectric material CdS; for the second one, CdS layer is inserted between NPB and ITO; for the third one, it is inserted between Alq3 and LiF and for the fourth one, it is inserted both of them. From the current density-voltage characteristics, it is noticed that the current density of WOLEDs is higher than the others through inserting CdS between Alq3 and LiF under the sama condition. Only the current density of the second device increases. The reason is that the CdS thin layer absorbs part of the short wavelength blue-light emission and increases the electron injection of the device, and also the number and ratio of excitions increase correspondingly, so the brightness and efficiency of the device are improved.