Recent Progress in Ionic Iridium(III) Complexes for Organic Electronic Devices

Abstract

Ionic iridium(III) complexes are emerging with great promise for organic electronic devices, owing to their unique features such as ease of molecular design and synthesis, excellent photophysical properties, superior redox stability, and highly efficient emissions of virtually all colors. Here, recent progress on new material design, regarding photo- and electroluminescence is highlighted, including several interesting topics such as: i) color-tuning strategies of cationic iridium(III) complexes, ii) widespread utilization in phosphorescent light-emitting devices fabricated by not only solution processes but also vacuum evaporation deposition, and iii) potential applications in data record, storage, and sercurity. Results on anionic iridium(III) complexes and "soft salts" are also discussed, indicating a new related subject. Finally, a brief outlook is suggested, pointing out that ionic iridium(III) complexes should play a more significant role in future organic electronic materials technology.

Toward High‐Performance Vacuum‐Deposited OLEDs: Sublimable Cationic Iridium(III) Complexes with Yellow and Orange Electroluminescence

“…[35][36][37][38][39][40] However,i TMCs were deemed hard to evaporate due to their intrinsici onic nature and henceo nly appliedf or OLEDs with solution-processed rather than vacuum-deposited emissive material layers (EMLs), [41][42][43][44][45][46][47][48][49][50][51] until Wong et al and Zhang et al successively reported sublimable cationic iridium(III) complexes with large-sized ligands chelated to the iridium core. [54][55][56][57][58] Herein, we further develop as eries of four novel sublimable cationic iridium(III) complexesb earing an imidazole-type ancillary ligand and tetraphenylborate-type negative counter-ions, investigate their photophysical, electrochemical and thermal characteristics, produceh igh-performance yellow and orange electroluminescence,therefore open up the possibility of using iTMCsa salarge family of new phosphorescent emittersi n state-of-the-art vacuum-deposited OLEDs. [54][55][56][57][58] Herein, we further develop as eries of four novel sublimable cationic iridium(III) complexesb earing an imidazole-type ancillary ligand and tetraphenylborate-type negative counter-ions, investigate their photophysical, electrochemical and thermal characteristics, produceh igh-performance yellow and orange electroluminescence,therefore open up the possibility of using iTMCsa salarge family of new phosphorescent emittersi n state-of-the-art vacuum-deposited OLEDs.…”

Highly Stable and Efficient Light-Emitting Electrochemical Cells Based on Cationic Iridium Complexes Bearing Arylazole Ancillary Ligands

“…Nowadays, a wide variety of complexes has been designed and used to manufacture LEC devices covering the whole visible spectrum, 16,17,18,19 with high efficiencies, 20,21,22 top lifetimes, 23,24,25 and short turnon times. 26,27,28 However, it is still to be found a complex that allows the fabrication of a device that reunites all those characteristics and becomes suitable for real-life lighting applications.…”

Boron‐Functionalized Phosphorescent Iridium(III) Complexes

“…Generally, an Ir III complex consists of an Ir center and three bidentate ligands, connecting to the Ir atom through C or N. [15] Thus, organoboron groups can be introduced into the different ligands, or an organoboron group itself can even act as a chelating unit. The photophysical properties (including emission colors and quantum yields) of Ir III complexes can be manipulated through the organoboron groups involved in the ligands.…”