Hyperbranched copolyfluorene from a 2,4,7-trifunctional fluorene monomer

Lin Ren Tsai, Yun Chen

研究成果: Article同行評審

18 引文 斯高帕斯(Scopus)

摘要

A new hyperbranched (P1) and linear copolyfluorene (P2) were prepared from 2,4,7-trifunctional (branching) and 2,7-bifunctional fluorene monomer, respectively, by the Wittig reaction, followed with end-capping by aromatic oxadiazole groups, to study the effect of hyperbranch structure. The weight-average molecular weights (Mw) of P1 and P2, determined by gel permeation chromatography using polystyrene as standard, were 33,000 and 25,700, respectively. The polymers were readily soluble in common organic solvents and exhibited good thermal stability (Td > 400°C). Optical properties, both in solution and film state, were investigated using absorption and photoluminescence (PL) spectra. In film state, the absorption and PL spectra peaked at 401-425 nm and 480-495 nm, respectively. The P1 showed energy funnel effect and enhanced fluorescence efficiency owing to hyperbranched structure and terminal oxadiazole groups. The HOMO and LUMO levels of P1 (P2), estimated from cyclic vortammograms, are -5.34 (-5.25) eV and -2.94 (-2.94) eV, respectively. Two-layer polymer light-emitting diodes devices (ITO/PEDOT/Pl/Ca/Al) exhibited maximal luminance and luminous efficiency of 3630 cd/m2 and 0.78 cd/A, respectively, which are superior to its linear counterpart P2 (598 cd/m2, 0.11 cd/A).

原文English
頁(從 - 到)5541-5551
頁數11
期刊Journal of Polymer Science, Part A: Polymer Chemistry
45
發行號23
DOIs
出版狀態Published - 2007 12月 1

All Science Journal Classification (ASJC) codes

  • 聚合物和塑料
  • 有機化學
  • 材料化學

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