Towards high performance solution-processed orange organic light-emitting devices: precisely-adjusting properties of Ir(iii) complexes by reasonably engineering the asymmetric configuration with second functionalized cyclometalating ligands

Abstract

By reasonably engineering the asymmetric configuration with purposely selected second ligands, the complex SIrB exhibits outstanding electroluminescence performance with peak EQE, CE, and PE of 23.2%, 66.5 cd A−1, and 56.0 lm W−1, respectively.

Detailed Molecular and Structural Analysis of Dual Emitter IrQ(ppy)2 Complex

“…Ir(III) complex 8-hydroxyquinoline-bis (2-phenylpyridyl) iridium (IrQ(ppy) 2 ) organometallic compound was chemically synthesized with two types of ligand: 2-phenylpyridine and quinoline, in a standard two-step reaction procedure, described previously [7]. Briefly, a mixture of iridium chloride hexahydrate and 2-phenylpyridine in 2-ethoxyethanol was refluxed in an argon atmosphere for 12 h at 150 • C. The yellow precipitate was cooled at room temperature and washed with ethanol and then dried in vacuum forming a [(CˆN) 2 Ir-µ-Cl] 2 bridged dimer.…”

“…The use of organometallic compounds in new technologies such as organic light-emitting diodes (OLED) [1][2][3][4][5][6][7][8], photovoltaic applications [9] or catalysis [10], requires different approaches during the chemical synthesis of these compounds, going from the photoluminescence, electroluminescence and internal quantum efficiency to the charge transport and the amorphous-crystalline interplay between these organometallic molecules [11][12][13][14][15][16][17][18].…”

Organometallic Coatings for Electroluminescence Applications

“…Sun et al for the asymmetric configuration of Ir(III) complexes, for which the electroluminescence at 15 V varies between 9713 and 25183 cd/m 2 . The concentration of Ir(III) complexes varies between 6 and 10 wt.% [59]. Even lower parameters were obtained by H. Yang et al for the Ir(ppy) 3 (8 wt.% in CBP) for the brightness that varies between 2000 and 8000 cd/m 2 at 14 V, while the current efficiency is slightly higher from 15 to 18 cd/A at the same bias [31].…”

C1‐Symmetric [Ir(C^N1)(C^N2)(O^O)]‐Tris‐Heteroleptic Iridium(III)‐Complexes with the Preferentially Horizontal Orientation for High‐Performance Near‐Infrared Organic Light‐Emitting Diodes

“…Convincingly, these two factors, which are key to reliable NIR‐OLEDs, are highly associated with the specific excited state situations of the Ir(III)‐complexes (such as energy‐level and electron/charge transfer (CT) among the 3 MLCT/ 3 LC (LC = ligand‐centered; MLCT = metal‐to‐ligand charge transfer) of the 1 T state, etc.). [ 14 ] In light of the transformation [ 15 ] of the 1 T nature in the C 1 ‐symmetric tris ‐heteroleptic Ir(III)‐complex composed of an Ir(III) ion and three different ligands, it is of notable interest on expanding that novel molecule‐engineered strategy to Ir(III)‐complex‐based NIR‐emitters, which should fill in the blank after previously reported NIR‐emissive [Ir(C^N) 3 ]‐ [ 8 ] and [Ir(C^N) 2 (L^X)]‐heteroleptic [ 9–11 ] Ir(III)‐complexes. Indeed, for C 1 ‐symmetric tris ‐heteroleptic Ir(III)‐complexes, their evident advantage lies in the potentially enriched inventory ([Ir(C^N 1 )(C^N 2 )(L^X)] (L^X = O^O or N^N), [ 15,16 ] [Ir(C^N 1 )(C^N 2 )(C^N 3 )], [ 17 ] [Ir(C^N 1 )(C^C 2 )(C^N 3 )], [ 18 ] [Ir(C^N 1 )(N^N 1 )(N^N 2 )], [ 19 ] etc.)…”