title: Electronic properties of silole-based organic semiconductors.
abstract: We report on a detailed quantum-chemical study of the geometric structure and electronic properties of 2,5-bis(6(')-(2('),2(")-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole (PyPySPyPy) and 2,5-di- (3-biphenyl)-1,1-dimethyl-3,4-diphenylsilole (PPSPP). These molecular systems are attractive candidates for application as electron-transport materials in organic light-emitting devices. Density Functional Theory (DFT), time-dependent DFT, and correlated semiempirical (ZINDO/CIS) calculations are carried out in order to evaluate parameters determining electron-transport and optical characteristics. Experimental data show that PyPySPyPy possesses an electron-transport mobility that is significantly greater than PPSPP, while PPSPP has a significantly larger photoluminescence quantum yield; however, the theoretical results indicate that the two systems undergo similar geometric transformations upon reduction and have comparable molecular orbital structures and energies. This suggests that intermolecular interactions (solid-state packing, electronic coupling) play significant roles in the contrasting performance of these two molecular systems.
authors.affiliation: School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA.
authors.forename: C
authors.initials: C
authors.lastname: Risko
authors.forename: G P
authors.initials: GP
authors.lastname: Kushto
authors.forename: Z H
authors.initials: ZH
authors.lastname: Kafafi
authors.forename: Z H
authors.initials: ZH
authors.lastname: Kafati
authors.forename: J L
authors.initials: JL
authors.lastname: Brédas
mesh_terms: D000042:Absorption; D002625:Chemistry, Organic / Q000379:methods*; D004583:Electrons; D007477:Ions; D008956:Models, Chemical; D008958:Models, Molecular; D015233:Models, Statistical; D017646:Organosilicon Compounds / Q000737:chemistry*; D011789:Quantum Theory; D012666:Semiconductors; D013997:Time Factors
chemical_list: C515692:2,5-bis(6'-(2',2''-bipyridyl))-1,1-dimethyl-3,4-diphenylsilole; C515693:2,5-di-(3-biphenyl)-1,1-dimethyl-3,4-diphenylsilole; D007477:Ions; D017646:Organosilicon Compounds