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  • 02월 19일 23시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제119회 대한화학회 학술발표회, 총회 및 기기전시회 안내 Dendrimers Containing Organometallic Complex Designed for Functions: Photoinduced Electron and Energy Transfer [우수포스터상]

2017년 2월 9일 16시 23분 45초
IND.P-9 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
4월 20일 (목요일) 11:00~12:30
저자 및
차현욱, 김철훈, 강상욱, 손호진*
고려대학교 신소재화학과, Korea
Luminescent dendrimers have largely been used as ligands for transition-metal. The resulting properties are (i) shielded excited states from quenching processes, (ii) light harvesting, (iii) conversion of incident UV light into visible or infrared emission, and (iv) metal ion sensing with signal amplification. We prepared dendrimers of heteroleptic iridium(III) complexes, Czn-Ir(dpq) (Gn, n = 0–2), which have the carbazole-functionalized dendron. Upon exciting the carbazole chromophore of G1 and G2 at 309 nm both the carbazole fluorescence and the MLCT emission were very weak at room temperature. These observations demonstrate that both the excited singlet state of carbazole and the triplet MLCT state of the Ir(dpq) core are efficiently quenched in the dendrimers. Since the apparent quenching of either carbazole fluorescence or MLCT emission observed at room temperature does not occur at 77 K, the temperature-dependent emission behavior of G1 and G2 for both the carbazole fluorescence and the MLCT phosphorescence was attributed to the participation of activated processes, that is, electron transfer from excited-singlet carbazole to the Ir(dpq) core. On the other hand, the increase in phosphorescence efficiency was estimated by the energy transfer mechanism for Ir(pic-Czn) (Gn, n = 0–3). Selective excitation of the Czn units of G1–G3 resulted in >90% quenching of the Cz fluorescence accompanied by the growth of phosphorescence from the Ir(pic) core as a consequence of energy transfer from the excited-singlet Czn chromophore to the core. Finally, the light-harvesting efficiencies for dendrimers were determined to be 162–334%.