Synthesis of laterally attached side-chain liquid crystalline poly(p-phenylene vinylene) and polyfluorene derivatives for the application of polarized electroluminescence

Yung Hsin Yao, Sheng-Hsiung Yang, Chain-Shu Hsu*

*Corresponding author for this work

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

Two series of poly(p-phenylene vinylene) and polyfluorene derivatives (PPV1-PPV4 and PF1-PF5) containing laterally attached penta(p-phenylene) mesogenes were synthesized and characterized. These polymers show nematic liquid crystalline behavior. The optical properties of the polymers were investigated by UV-vis absorption and photoluminescence spectrometers and these polymers were fabricated to form the polarized electroluminescent devices using poly(ethylenedioxythiophene)-poly(styrene sulfonic acid) (PEDOT-PSS) as an alignment layer. In the series of poly(p-phenylene vinylene) derivatives, polymer PPV4 offered the best EL device performance. It emitted yellow light at 588 nm at 4 V. The maximum brightness was about 1337 cd/m2 at 9 V with a polarized ratio of 2.6. In another series of polyfluorene derivatives, PF4 offered the best EL device performance with the polarized ratio of 12.4 and a maximum luminescence of 1855 cd/m2. In the case of polarized white light, as a consequence of blending small amount of PF4 and PF5 with a host polymer PF2, polarized ratio of up to 10.2 and a maximum brightness of 2454 cd/m2 have been attained. The aligned films exhibited pronounced polarized ratio, implying that the polymers exhibit potential for linearly polarized LED application.

Original languageEnglish
Pages (from-to)8297-8308
Number of pages12
JournalPolymer
Volume47
Issue number25
DOIs
StatePublished - 22 Nov 2006

Keywords

  • Polarized light
  • Poly(p-phenylene vinylene)
  • Polyfluorene

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