Park Young Wook, Kim Young Min, Choi Jin Hwan, Park Tae Hyun, Jeong Jin-Wook, Cho Min Ju, Choi Dong Hoon, Ju Byeong Kwon
Display and Nanosystem Laboratory, College of Engineering, Korea University, 5 Anam-dong, Sungbuk-gu, Seoul 136-713, Republic of Korea.
J Nanosci Nanotechnol. 2010 May;10(5):3250-3. doi: 10.1166/jnn.2010.2279.
The tris(2-phenylpyridine)iridium(III) [Ir(ppy)3] is a well known highly efficient green light-emitting phosphorescent guest dye dopant, but its relatively low solubility has been obstructing it to be used in polymer light-emitting diodes (PLEDs). According to our latest reports the solubility of Ir(ppy)3 complexes with the carbazole ligands, i.e., Ir(Czppy)3, was improved significantly in organic solvents, and was sufficient to be used in soluble process. This highly soluble Ir(Czppy)3 complex showed remarkably higher photoluminescence characteristics than conventional Ir(ppy)3, but it showed similar or comparably better electroluminescence (EL) characteristics, when the PLED was composed by widely used conventional hole blocking layer (HBL) and electron transport layer; 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline and tris(8-hydroxyquinoline)aluminum, respectively. In this report, we applied various HBLs to improve the EL characteristics of soluble Ir(III) complex based phosphorescent PLEDs. The PLEDs utilized by the wide band-gap 3-(4-biphenylyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole demonstrated highly improved the current and the external quantum efficiency of 17.61 cd/A and 6.42%, respectively.
三（2-苯基吡啶）铱（III）[Ir（ppy）3]是一种众所周知的高效绿色发光磷光客体染料掺杂剂，但其相对较低的溶解度阻碍了它在聚合物发光二极管（PLED）中的应用。根据我们的最新报告，Ir（ppy）3与咔唑配体形成的配合物，即Ir（Czppy）3，在有机溶剂中的溶解度显著提高，足以用于可溶过程。这种高溶解性的Ir（Czppy）3配合物显示出比传统的Ir（ppy）3更高的光致发光特性，但当PLED由广泛使用的传统空穴阻挡层（HBL）和电子传输层；分别为2,9-二甲基-4,7-二苯基-1,10-菲咯啉和三（8-羟基喹啉）铝组成时，它显示出相似或相当更好的电致发光（EL）特性。在本报告中，我们应用了各种HBL来改善基于可溶性Ir（III）配合物的磷光PLED的EL特性。由宽带隙3-（4-联苯基）-4-苯基-5-叔丁基苯基-1,2,4-三唑制成的PLED分别实现了17.61 cd/A的电流和6.42%的外量子效率的显著提高。
