Presenter: Prof. Sung-Ho Jin, Pusan National University, Korea
Time: 10:00AM on Jan. 29th (Thursday)
Location: Conference Room B, BLDG 909-1F
We have synthesized the various colors of phosphorescent Ir(III) complexes for phosphorescent organic light-emitting diodes (PhOLEDs) applications. A new series of highly efficient deep-blue phosphorescent Ir(III) complexes, (F2CH3ppy)2Ir(pic-N-oxide) and (F2CF3CH3ppy)2Ir(pic-N-oxide), based on phenylpyridine (ppy) as the main ligand and picolinic acid N-oxide (pic-N-oxide) as the ancillary ligand, were synthesized for applications in PhOLEDs. High performance PhOLEDs fabricated using the (F2CH3ppy)2Ir(pic-N-oxide) and (F2CF3CH3ppy)2Ir(pic-N-oxide) showed bright deep blue emissions with the Commission Internationale de L’Eclairage (CIE) coordinates of (0.147, 0.210) at the current density of 0.1 mA/cm2, and high external quantum (23.3%) and current (36.1 cd/A) efficiencies. We also synthesized a mixed homoleptic iridium(III) complexes, iridium(III) bis(2-phenylpyridinato-N,C2’) (2-(2’,4’-difluorophenyl)-4-methylpyridine), (ppy)2Ir(dfpmpy) and iridium(III) bis(2-(2’,4’-difluorophenyl)-4-methylpyridinato- N,C2’) (2-phenylpyridine), (dfpmpy)2Ir(ppy) using phenylpyridine as a main skeleton for bluish green PhOLEDs. The PhOLEDs with the mixed homoleptic Ir(III) complexes showed excellent performances approaching 100% internal quantum efficiency with a very high external quantum efficiency (EQE) of ~27%, a low turn-on voltage of 2.4 V, high power efficiency of ~85 lm/W, and very low efficiency roll-off up to 20,000 cd/m2. Recently, we reported a highly efficient and soluble red-emitting tris(4-phenyl-2-(thiophen-2-yl)quinoline)iridium(III) complex, (Th-PQ)3Ir, that was designed and successfully synthesized for use in solution-processed PhOLED. Upon replacing the benzene in the cyclometalated phenylquinoline main ligand by thiophene shifts PL emission to red and enhances thermal stability. PhOLED with (Th-PQ)3Ir was successfully fabricated with a GraHIL as high work function HIL and a mixed host EML, which is composed of electron and hole transporting host materials (TCTA, TPBI). Using this simple structure, we achieved a PhOLED with very high luminous current efficiency of ~ 26 cd/A and EQE of ~ 21% with good CIE coordinates (0.64, 0.34). And also, two heteroleptic Ir(III) complexes, TPQIr-ET and TPQIr were designed, synthesized, and applied as a dopant for solution-processed deep-red PhOLEDs. We introduced the electron transport (ET) group to the ancillary ligand of dopant materials to improve the balanced charge carrier injection in the devices. As a result, TPQIr-ET shows the EQE of 20.59%, which is 25% higher than that of the TPQIr.
Sung-Ho Jin was born in Pusan, Korea, in 1964. He received his B.S. degree in Chemistry from Pusan National University in 1988 and his Ph.D. in Chemistry from the Korea Advanced Institute of Science andTechnology (KAIST) in 1993. In the same year he joined the Samsung Advanced Institute of Technology (SAIT) as a Senior Researcher where he worked in the field of Display Division. Sung Ho Jin was first designed and organized the AMOLED project in 1994 and then managed the AMOLED project by 1999. He joined the faculty of Pusan National University in 1999. His main research interests are (1) organic and polymer lightemitting diodes (2) organic solar cells (3) perovskite solar cells, and (4) synthesis of new functional polymers (conducting polymers, side chain liquid crystal polymers, photo-alignment materials for liquid crystal display). He is the author or coauthor of over 382 publications and 61 patents.
Contact: Prof. Zuoquan Jiang