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dc.contributor.author이상욱-
dc.date.accessioned2016-05-10T00:55:05Z-
dc.date.available2016-05-10T00:55:05Z-
dc.date.issued2015-01-
dc.identifier.citationCHEMISTRY - A EUROPEAN JOURNAL, v. 21, NO 5, Page. 2052-2061en_US
dc.identifier.issn1521-3765-
dc.identifier.urihttp://hdl.handle.net/20.500.11754/21106-
dc.identifier.urihttp://onlinelibrary.wiley.com/doi/10.1002/chem.201405433/abstract;jsessionid=761CCC6E2A8812A49A73DD77490DBF3F.f02t04?systemMessage=Pay+Per+View+on+Wiley+Online+Library+will+be+unavailable+on+Saturday+15th+April+from+12%3A00-09%3A00+EDT+for+essential+maintenance.++Apologies+for+the+inconvenience.-
dc.description.abstractA series of [(C^N)2Ir(acac)] complexes [{5-(2-R-CB)ppy}2Ir(acac)] (3 a–3 g; acac=acetylacetonate, CB=o-carboran-1-yl, ppy=2-phenylpyridine; R=H (3 a), Me (3 b), iPr (3 c), iBu (3 d), Ph (3 e), CF3C6H4 (3 f), C6F5 (3 g)) with various 2-R-substituted o-carboranes at the 5-position in the phenyl ring of the ppy ligand were prepared. X-ray diffraction studies revealed that the carboranyl C[BOND]C bond length increases with increasing steric and electron-withdrawing effects from the 2-R substituents. Although the absorption and emission wavelengths of the complexes are almost invariant to the change of 2-R group, the phosphorescence quantum efficiency varies from highly emissive (ΦPL≈0.80 for R=H, alkyl) to poorly emissive (R=aryl) depending on the 2-R group and the polarity of the medium. Theoretical studies suggest that 1) the almost nonemissive nature of the 2-aryl-substituted complexes is mainly attributable to the large contribution to the LUMO in the S1 excited state from an o-carborane unit and 2) the variation in the C[BOND]C bond length between the S0 and T1 state structures increases with increasing steric (2-alkyl) and electronic effects (2-aryl) of the 2-R substituent and the polarity of the solvent. The solution-processed electroluminescence (EL) devices that incorporated 3 b and 3 d as emitters displayed higher performance than the device based on the parent [(ppy)2Ir(acac)] complex. Along with the high phosphorescence efficiency, the bulkiness of the 2-R-o-carborane unit is shown to play an important role in improving device performance.en_US
dc.description.sponsorshipThis work was supported by the Basic Science Research Program (NRF-2012R1A1A2039773 for M.H.L. and NRF-2013R1A1A2058722 for Y.H.L.) and the Priority Research Centers program (2009-0093818) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education. J.L. thanks to the financial support from the NRF (NRF-2014R1A1A1002224) funded by the Ministry of Science, ICT & Future Planning. S.U.L. would like to express sincere thanks to the staff of the Center for Computational Materials Science of the Institute for Materials Research (Tohoku University) for their continuous support of the SR16000 supercomputing facilities.-
dc.language.isoenen_US
dc.publisherWILEY-V C H VERLAG GMBHen_US
dc.subjectCarboranesen_US
dc.subjectIridiumen_US
dc.subjectOrganic light-emitting diodesen_US
dc.subjectPhotophysicsen_US
dc.subjectQuantum efficiencyen_US
dc.titleManipulation of Phosphorescence Efficiency of Cyclometalated Iridium Complexes by Substituted o-Carboranesen_US
dc.typeArticleen_US
dc.relation.no5-
dc.relation.volume21-
dc.identifier.doi10.1002/chem.201405433-
dc.relation.page2052-2061-
dc.relation.journalCHEMISTRY-A EUROPEAN JOURNAL-
dc.contributor.googleauthorLee, Young Hoon-
dc.contributor.googleauthorPark, Jihyun-
dc.contributor.googleauthorJo, Song-Jin-
dc.contributor.googleauthorKim, Miyoung-
dc.contributor.googleauthorLee, Junseong-
dc.contributor.googleauthorLee, Sang Uck-
dc.contributor.googleauthorLee, Min Hyung-
dc.relation.code2015002776-
dc.sector.campusS-
dc.sector.daehakGRADUATE SCHOOL[S]-
dc.sector.departmentDEPARTMENT OF BIONANOTECHNOLOGY-
dc.identifier.pidsulee-
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GRADUATE SCHOOL[S](대학원) > BIONANOTECHNOLOGY(바이오나노학과) > Articles
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