Record-High Efficiency Blue-Green Cationic Ir(III) Complexes for Light-Emitting Electrochemical Cells with EQE Approaching 40

• Published in: Inorganic chemistry Vol. 64; no. 21; pp. 10402 - 10413
• Main Authors: Huang, Yu-Ting, Chang, Chung-Chieh, Chang, Che-Lun, Hsu, Wei-Tse, Li, Yun-Rong, Yang, Zu-Po, Lu, Chin-Wei, Su, Hai-Ching
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 02.06.2025
• ISSN: 0020-1669; 1520-510X; 1520-510X
• DOI: 10.1021/acs.inorgchem.5c00167

Light-emitting electrochemical cells (LECs) provide a cost-effective solution for lighting applications and are well-suited for large-area and industrial-scale manufacturing. However, enhancing the efficiency of LECs remains a significant challenge. To address this issue, this study presents a series of blue-green iridium complexes with promising phosphorescent emission properties. Among these, di­[1-(2,4-difluorophenyl)-pyrazolyl]-5,5′-difluoro-2,2′-bipyridyl iridium­(III) hexafluorophosphate stands out, demonstrating exceptional performance. Following optimizing the device with varying thicknesses, an EQE of 16.8% and a current efficiency of 47.2 cd A–1 were attained. Further enhancements through the integration of a diffusive layer resulted in a 270% increase in efficiency, reaching an EQE of 39.3% and current efficiency of 109.6 cd A–1. This efficient technology demonstrates significant potential and lays the groundwork for future high-performance light-emitting devices.