Synthesis of new iridium complexes and their electrophosphorescent properties in polymer light-emitting diodes

High-efficiency solution processable electrophosphorescent iridium complexes bearing polyphenylphenyl dendron ligands

“…The maximum emission wavelengths of the EL spectra of the devices are from 549 nm to 640 nm. [6,7,20], while the EL efficiencies of 5 cd/A (>5%) for saturated red emission materials of Complexes E and F are also comparable to most of the reference reported results for solution processed devices [9,22]. From the device energy level diagram in Fig.…”

“…Obviously, such a drawback will limit the application of iridium complexes for OLEDs. To address this issue, bulky ligands have been used to prevent interactions between Ir-complex molecules and the performance of devices fabricated from these compounds has improved [19,20]. For example, dendrimer type iridium complexes have been demonstrated to prevent the interaction between molecules in solid state effectively and highly efficient OLED devices have been achieved through solution process fabrication with these materials [21][22][23][24][25].…”

A novel cyclometalated Iridium(iii) complex containing dibenzo-24-crown-8: synthesis, luminescence and application in highly efficient green phosphorescent OLEDs

“…3 The most widely used homoleptic green emitting iridium complex, fac-tris[2-phenylpyridinato]Ir(III) [fac-Ir(ppy) 3 ], derivatives have shown a number of advantages such as ease of tuning emission energy by functionalizing the ligand of ppy with electron donating and electron withdrawing substituents and high phosphorescent quantum efficiency at room temperature. 9 In order to achieve high-efficiency solution-processable green phosphorescent PLEDs, in this contribution, the iridium complexes, whose ppy ligand was modied by group of dibenzo-24-crown-8, were synthesized and emitted green light with a F PL ranging from 0.56 to 0.63. 4 Ir(ppy) 3 in degassed toluene shows very strong phosphorescence (l max ¼ 514 nm, photoluminescence quantum yield F PL ¼ 0.4) emitted from the predominantly 3 MLCT (metal-to-ligand charge transfer) excited state at room temperature.…”

Anthracene‐Cored Dendrimer for Solution‐Processible Blue Emitter: Syntheses, Characterizations, Photoluminescence, and Electroluminescence

“…[4][5][6][8][9][10][11] It is important to note, besides the core and dendrons, [4][5][6][7][8][9][10][11]25] the solubilizing alkyl/alkyloxyl (peripheral) groups in a dendrimer could affect the device performances largely, as the early work in our laboratory studied the effects of a variety of alkyl substituents of phosphorescent iridium complexes on the performances of doped polymer-light emitting diodes. [26] The choice of appropriate solubilizing groups is becoming more important in molecular and dendritic materials since the molecular weight is generally at the level from a few hundred to several thousand. The encouraging electroluminescent characteristics of EH-G2AN is certainly related to the unique structure presented by the 9,10-anthracenyl-cored dendrimer with 1,3,5-phenylene-based rigid dendrons tethered by the ''solubilizing and protective'' groups, which efficiently prevents the formation of any appreciable aggregation and thus potential excimers in the solid state, as inferred from the photoluminescent studies.…”

“…The residue was purified with column chromatography using petroleum ether/dichloromethane (v/v ¼ 5/1) and then petroleum ether/dichloromethane (v/v ¼ 1/ 1) as eluent to afford a colorless oil (1. 26 Preparation of the Second-Generation Dendronic Bromide 3 Pd(PPh 3 ) 4 (38 mg, 0.033 mmol) was added to a mixture of 2 (1.23 g, 2 mmol) and 1,3,5-tribromobenzene (0.29 g, 0.92 mmol) in toluene (20 ml), ethanol (10 ml), and Na 2 CO 3 aqueous solution (2 M, 10 ml) under a nitrogen atmosphere. The reaction was heated to reflux at 110 8C for 24 h. After cooling to the room temperature, the mixture was poured into water and extracted with dichloromethane.…”