Fast synthesis of iridium() complexes with sulfur-containing ancillary ligand for high-performance green OLEDs with EQE exceeding 31

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 7; no. 24; pp. 7273 - 7278
• Main Authors: Lu, Guang-Zhao, Tu, Zhen-Long, Liu, Liang, Zhang, Wen-Wei, Zheng, You-Xuan
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 2019
• Subjects: Coordination compounds; Crystallography; Current efficiency; Density distribution; Diodes; Efficiency; Emission spectra; Emitters; Iridium compounds; Ligands; Organic light emitting diodes; Photoluminescence; Quantum efficiency; Sulfur
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c9tc01397k

Three green iridium( iii ) cyclometalated complexes, namely, (4tfmppy) 2 Ir(dipdtc), (24btfmppy) 2 Ir(dipdtc), and (TN 4 T) 2 Ir(dipdtc), with the sulfur-containing ancillary ligand N , N -diisopropyldithiocarbamate (dipdtc) were synthesized within 15 min at room temperature. The emission colors ( λ peak = 497-534 nm) and photoluminescence quantum efficiencies ( Φ P = 71.6-94.2%) can be effectively regulated by introducing different main ligands, namely, 2-(4-(trifluoromethyl)phenyl)pyridine (4tfmppy), 2-(2,4-bis(trifluoromethyl)phenyl)pyridine (24btfmppy), and 2′,6′-bis(trifluoromethyl)-2,4′-bipyridine (TN 4 T). Employing these complexes as emitters, organic light-emitting diodes (OLEDs) with double-emitting layers were fabricated. In particular, the device based on the (TN 4 T) 2 Ir(dipdtc) complex showed superior performances with maximum current efficiency of 86.59 cd A −1 and maximum external quantum efficiency of 31.24% with low efficiency roll-off. These results suggest that the Ir( iii ) complexes with a four-membered ring Ir-S-C-S backbone containing dipdtc have potential applications in OLEDs. Three green iridium( iii ) complexes were rapidly synthesized at room temperature with a sulfur-containing ligand, and OLEDs fabricated using them show high performances with EQE max of 31.24% and low efficiency roll-off.