Design and Synthesis of Asymmetric Au(III) Complexes Exhibiting Bright Anisotropic Emission for High‐Performance Organic Light‐Emitting Diodes

• Published in: Advanced optical materials Vol. 11; no. 12
• Main Authors: Kuo, Hsin‐Hung, Kumar, Sudhir, Omongos, Rashen Lou, T. do Casal, Mariana, Usteri, Marc Eduard, Wörle, Michael, Escudero, Daniel, Shih, Chih‐Jen
• Format: Journal Article
• Language: English
• Published: 01.06.2023
• Subjects: anisotropic emission; electroluminescence; luminescent Au(III) complexes; organic light‐emittting diodes; transition dipole moment orientation
• ISSN: 2195-1071; 2195-1071
• DOI: 10.1002/adom.202202519

Organic light‐emitting diodes (OLEDs) are emerging as one of the most promising candidates for next‐generation optoelectronics. However, most commercial OLED displays are fabricated using organometallic phosphors containing rare transition metals, such as Ir(III) and Pt(II). Recently, the development of efficient phosphorescent emitters based on abundant Au(III) is drawing considerable attention. Here, rational molecular design of a series of Au(III) organometallic complexes consisting of asymmetric C^C^N ligands and carbazole moieties functionalized by phenyl or mesityl groups is presented. The synthesized complexes exhibit shortened radiative lifetimes, and reach improved photoluminescence quantum yield, ηPL, of greater than 93% in thin films. Moreover, the asymmetric molecular design induces anisotropic emission with a high ratio of horizontally oriented transition dipole moment of up to 82% in host‐guest films. Accordingly, high‐performance OLED devices with record‐high external quantum efficiencies, ηext, and current efficiencies, ηCE, of up to 27% and 89 cd A−1, respectively, are demonstrated. It is believed that the molecular design of anisotropic Au(III) emitters will be greatly facilitated by the fundamental principles and theoretical analysis presented here. Here, a series of Au(III) organometallic complexes consisting of asymmetric C^C^N ligands and carbazole moieties functionalized by phenyl or mesityl groups is presented. The Au(III) complexes exhibit short radiative lifetimes and high photoluminescence quantum yield, up to 93%, with a high ratio of horizontally oriented transition dipole moment of up to 82% in host–guest films. Finally, organic light‐emitting diode devices with record‐high external quantum efficiencies of up to 27% and current efficiencies of 89 cd A–1 are demonstrated.