报告人：Sung-Ho Jin 教授

Department of Chemistry Education, Graduate Department of Chemical Materials and Institute for Plastic Information and Energy Materials, Pusan National University, Busan, 609-735, Republic of Korea

题目：Development of Highly Efficient Multi-Functional Emitting Materials for

Organic Light-Emitting Diode Applications

时间：2015年1月29日（星期四）上午10:00am

地点：独墅湖校区909号楼一楼B会议室

摘要：

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.