標題: Cationic Ir-III Emitters with Near-Infrared Emission Beyond 800 nm and Their Use in Light-Emitting Electrochemical Cells
作者: Chen, Guan-Yu
Chang, Bo-Ren
Shih, Ting-An
Lin, Chien-Hsiang
Lo, Chieh-Liang
Chen, Yan-Zhi
Liu, You-Xuan
Li, Yu-Ru
Guo, Jin-Ting
Lu, Chin-Wei
Yang, Zu-Po
Su, Hai-Ching
光電系統研究所
照明與能源光電研究所
Institute of Photonic System
Institute of Lighting and Energy Photonics
關鍵字: electrochemistry;iridium;ligand effects;luminescence;nitrogen heterocycles
公開日期: 11-Apr-2019
摘要: Solid-state near-infrared (NIR) light-emitting devices have recently received considerable attention as MR light sources that can penetrate deep into human tissue and are suitable for bioimaging and labeling. in addition, solidstate NIR light-emitting electrochemical cells (LECs) have shown several promising advantages over NIR organic light-emitting devices (OLEDs). However, among the reported NIR LECs based on ionic transition-metal complexes (iTMCs), there is currently no iridium-based LEC that displays NIR electroluminescence (EL) peaks near to or above 800 nm. In this report we demonstrate a simple method for adjusting the energy gap between the highest-occupied molecular orbital (HOMO) and the lowest-unoccupied molecular orbital (LUMO) of iridium-based iTMCs to generate NIR emission. We describe a series of novel ionic iridium complexes with very small energy gaps, namely NIR1-NIR6, in which 2,3-diphenylbenzo[g]quinoxaline moieties mainly take charge of the HOMO energy levels and 2,2'-biquinoline, 2-(quinolin-2-yl)quinazoline, and 2,2'-bibenzo[d]thiazole moieties mainly control the LUMO energy levels. All the complexes exhibited NIR phosphorescence, with emission maxima up to 850 nm, and have been applied as components in LECs, showing a maximum external quantum efficiency (EQE) of 0.05% in the EL devices. By using a host-guest emissive system, with the iridium complex RED as the host and the complex NIR3 or NIR6 as guest, the highest EQE of the LECs can be further enhanced to above 0.1%.
URI: http://dx.doi.org/10.1002/chem.201805902
http://hdl.handle.net/11536/151923
ISSN: 0947-6539
DOI: 10.1002/chem.201805902
期刊: CHEMISTRY-A EUROPEAN JOURNAL
Volume: 25
Issue: 21
起始頁: 5489
結束頁: 5497
Appears in Collections:Articles