Red emissive organic light-emitting diodes based on codeposited inexpensive Cu super(I) complexes

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2015-05, Vol.3 (22), p.5835-5843
• Main Authors: Ni, Tianchi, Liu, Xiaochen, Zhang, Tao, Bao, Hongliang, Zhan, Ge, Jiang, Nan, Wang, Jianqiang, Liu, Zhiwei, Bian, Zuqiang, Lu, Zhenghong, Huang, Chunhui
• Format: Article
• Language: English
• Subjects: Codeposition; Doped films; Emissivity; Illumination; Luminance; Markets; Natural resources; Organic light emitting diodes; Sublimation
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c5tc00727e

Inexpensive materials made of abundant natural resources such as Cu super(I) complexes are essential to sustain the development of organic light emitting diode (OLED) technology for mass market applications such as solid-state illumination. Cu super(I) complexes, however, mostly are neither soluble nor stable toward sublimation, which is a road block for the development of efficient Cu super(I) complex based OLEDs using traditional methods of synthesis, sublimation and vacuum evaporation. In this work, two isoquinolyl carbazole (CIQ) compounds 9-(8-(carbazol-9-yl)isoquinolin-5-yl)-carbazole (DCIQ) and 9-(4-(5-(4-(carbazol-9-yl)phenyl)isoquinolin-8-yl)phenyl)-carbazol e (DCDPIQ) were synthesized to codeposition with copper iodide (CuI) to form red emissive dimeric Cu super(I) complex doped film in situ, which could be utilized directly as the emissive layer (EML) in OLEDs. After a systematic study of the two compounds and their codeposited CuI : CIQ films, as well as optimizing the CuI doping concentration, it is found that red OLEDs can be achieved, showing a maximum emission band, an external quantum efficiency (EQE), a luminance of 643 nm, 3.5%, 3290 cd m super(-2) for DCIQ, and 635 nm, 3.6%, 853 cd m super(-2) for DCDPIQ, respectively.