Electronic properties of silole-based organic semiconductors.

C Risko, G P Kushto, Z H Kafafi, Z H Kafati, J L Brédas

School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA.

The Journal of chemical physics 2004 Nov 8

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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. Copyright 2004 American Institute of Physics.

Citation

C Risko, G P Kushto, Z H Kafafi, Z H Kafati, J L Brédas. Electronic properties of silole-based organic semiconductors. The Journal of chemical physics. 2004 Nov 8;121(18):9031-8