Acta Phys. -Chim. Sin. ›› 2009, Vol. 25 ›› Issue (02): 347-352.doi: 10.3866/PKU.WHXB20090226

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Electronic Structures and Spectroscopic Properties of 4-[(1,2-Diphenyl)-4’-(N,N-diphenyl-4-vinylbenzenamine)] Biphenyl and Its Difluorinated Derivatives

CUI Ming-Xia; DONG Shi-Hong; WANG Wen-Liang; YIN Shi-Wei; LV Jian   

  1. Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry and Materials Science, Shaanxi Normal University, Xi’an 710062, P. R. China; Xi’an Institute of Modern Chemistry, Xi’an 710065, P. R. China
  • Received:2008-09-08 Revised:2008-10-31 Published:2009-01-16
  • Contact: WANG Wen-Liang

Abstract: Electronic structures and spectroscopic properties of 4-[(1,2-diphenyl)-4’-(N,N-diphenyl-4-vinylbenzenamine)] biphenyl and its difluorinated derivatives were studied. B3LYP/6-31G(d) and CIS/6-31G(d)methods were used to optimize the ground and excited state geometries, respectively, and the data for ionization potentials (IPs) and electron affinities (EAs) were also obtained. Absorption and emission spectra were calculated using time-dependent density functional theory (TD-DFT) based on ground and excited state geometries.We found that the main emission peak intensity at 469-474 nmis far more larger than the second emission peak at 372-387 nm, which indicates that this type of compound has its own highly pure emission wavelength. Difluoro-substituted derivatives on the benzene of the main chain (B, C and D) cause an energy lowering of the lowest unoccupied molecular orbital (LUMO) energy levels obviously, which facilitates the injection of electron carriers from the metal electrode. Difluoro-substituted derivatives on the benzene of benzenamine (D and E) cause an energy lowering of the highest occupied molecular orbitals (HOMO) obviously. The increasing of IP and energy gap, which is proper to hold hole transfer from the emission layer to the electron transport layer, reduces the formation of exciplexes at the interface and causes a blue-shift of spectra. The difluoro-substituted derivative of benzene on both the main chain and benzenamine (D) is better for a balance of electron and hole injection which should result in even better emission properties.

Key words: Distyrylarylene derivative, Density functional theory, Hole blocking, Spectroscopic property, Electronic structure


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