121st General Meeting of the KCS

Type Poster Presentation
Area Industrial Chemistry
Room No. Event Hall
Time 4월 19일 (목요일) 11:00~12:30
Code IND.P-14
Subject Photophysical Properties of Isomeric N-heterocyclic Carbene Ir (III) Complexes and Its Application to Blue Phosphorescent OLEDs
Authors So-Yoen Kim, Jin-Hyoung Kim, JEONG WAN YU, Chul Hoon Kim, Sang Ook Kang, Ho-Jin Son*
Department of Advanced Materials Chemistry, Korea University, Korea
Abstract Two isomeric N-heterocyclic carbene Ir(III) complexes, f-Ir-(dbfmi)3 and m-Ir-(dbfmi)3, were isolated and their systematic investigation on photophysical and electrochemical properties was carried out. Among them, the crystal structure of the meridional isomer, m-Ir-(dbfmi)3, is determined. The origin of phosphorescent emissions differs depending on the configurations of the two isomers. Both isomers, f-Ir-(dbfmi)3 and m-Ir-(dbfmi)3, showed efficient emission in dichloromethane solution with quantum yields of 68% and 53%, respectively, due to unusual properties of the N-heterocyclic carbene (NHC) ligand; –that is, the complexes possess a strong metal–ligand bond that destabilizes the non-radiative metal centred ligand-field states. Depending on their configurations, the two isomers showed slightly different excited states. Even though both isomers possess a largely 3LC character mixed with the 3MLCT character in their excited states, m-Ir-(dbfmi)3 showed higher 3MLCT character as evidenced by the solvent polarity dependence emission spectra and emission lifetime.
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