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제124회 대한화학회 학술발표회, 총회 및 기기전시회 안내 DFT/TD-DFT Study on the Geometric preference and Photo-chemical properties of Ir(PPy)2(L), L=PPy, Pic, bpy and acac

등록일
2019년 8월 29일 17시 02분 44초
접수번호
1906
발표코드
INOR.P-126 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
발표시간
10월 17일 (목요일) 11:00~12:30
발표형식
포스터
발표분야
Inorganic Chemistry
저자 및
공동저자
Dong-Seon Shin, Hojune Choi, Yun Hi Kim1,*, Bong Gon Kim*
Department of Chemical Education, Gyeongsang National University, Korea
1Department of Chemistry, Gyeongsang National University, Korea

Recently, Ir(PPy)3 is very attractive interested in research items for organic lighted emission diodes fields. And Ir(PPy)2(L), L is ancillary ligands as pic and bpy, are also many interested in complexes. These Ir(A-B)3 type octahedral complexes are consist on various geometrical isomer according to ancillary ligands. Ir(PPh)3 complexes presents two different geometrical isomers as facial and meridional, Ir(PPy)2(Pic) are presented four different geometrical isomers. In this study, four different octahedral Ir(III) complexes, Ir(PPy)2(L), L are ppy, bpy, acac and pic as ancillary ligands to identify geometrical preference and emission patterns. This includes structural properties, spectral properties, molecular orbital (MO) descriptions, and ionization energies. The latter is germane to OLED devices because the ionization energies and electron affinities (commonly referred to as the HOMO and LUMO energies, respectively) of the light-emitting molecules in the active layer need to be matched to the energy levels of the electrodes. According to results, The fac-Ir(ppy)3 having the lower energy. Because fac-Ir(ppy)3dominates in most environments, focus is on this species. Time-dependent density functional theory using B3LYP functional is used to calculate excited states of Ir(ppy)3 and a few low energy states of Ir(ppy)3 . The calculated T1 –S0 energy gap (2.30 eV) is in reasonable agreement with the experimental value of 2.44 eV. Equilibrium geometries are calculated for S0, T1, and the lowest cation state (D0), and several ionization energies are obtained: adiabatic (5.86 eV); vertical from the S0 equilibrium geometry (5.88 eV); and vertical ionization of T1 at its equilibrium geometry (5.87 eV). These agree with a calculation by Hay (5.94 eV), and with the conservative experimental upper bound of 6.4 eV. Molecular orbitals provide qualitative explanations. A calculated UV absorption spectrum, in which transitions are vertical from the S0 equilibrium geometry, agrees with the room temperature experimental spectrum. The calculated T1 –S0 energy gap (2.30 eV) is in reasonable agreement with the experimental value of 2.44 eV. Only a few percent of singlet character in T1 is needed to explain so short a phosphorescence lifetime as 200 ns, because of the large 1LC←S0 and 1MLCT←S0 absorption cross-sections. Equilibrium geometries are calculated for S0, T1, and the lowest cation state, and several ionization energies are obtained: adiabatic (5.86 eV); vertical from the S0 equilibrium geometry (5.88 eV); and vertical ionization of T1 at its equilibrium geometry (5.87 eV).


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