New blue phosphorescence from trifluorosulfonyl-substituted iridium complexes

• Published in: Dyes and pigments Vol. 163; pp. 684 - 691
• Main Authors: Ha, Yeon Hee, Sohn, Sunyoung, Han, Seung-Hoon, Kim, Bong Gon, Ahn, Hyungju, Jung, Sungjune, Kwon, Soon-Ki, Kim, Yun-Hi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.04.2019
• Subjects: Blue phosphorescence; Grazing incidence wide-angle X-ray diffraction; Iridium complex; Organic light emitting diodes; Preferential orientation along the out-of-plane direction; Organic light emitting diodes; Iridium complex; Preferential orientation along the out-of-plane direction; Blue phosphorescence; Grazing incidence wide-angle X-ray diffraction
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2018.12.062

For color-pure phosphorescence organic light emitting diodes (PHOLEDs), we synthesized the trifluoromethyl sulfonyl substituted ligand and two new blue Iridium complexes with perfluoro-sulfonyl group (SOCF3pic and SOCF3mpic). The both iridium complexes showed similar photophysical and thermal properties while the HOMO energy leves of two Iridium complexes slightly differnet to be −5.84 eV for SOCF3pic and −5.74 eV for SOCF3mpic, respectively. The device with the SOCF3mpic dopant exhibited higher device efficiencies of 7.17 cd/A and 3.7% compared to that with the SOCF3pic dopant (4.03 cd/A and 2.78%). Two-dimensional GIXD images of scattered X-ray intensity from surface to full depth for SOCF3pic-doped and SOCF3mpic-doped TCTA:4PTPS films were characterized for preferential orientation along the out-of-plane direction. [Display omitted] •Synthesized trifluoromethyl sulfonyl substituent blue phosphorescent dopants.•Decreased HOMO level due to a strong electron withdrawing group in the iridium complexes with perfluoro-sulfonyl group.•High current and external quantum efficiency of 7.17 cd/A and 3.70% in picolinate doped device with 3-methylpyridine (mpic) as the ancillary ligand.•SOCF3mpic-doped TCTA:4PTPS films has more preferential orientation along the out-of-plane direction.