New class of light-emitting polymers/oligomers

Oh Kil Kim, Han Young Woo, Jai Kyeong Kim, Zhennian Huang

Research output: Contribution to journalConference article

1 Citation (Scopus)

Abstract

Novel electro-/photoactive multifunctional dyes were synthesized based on dithienothiophene, DTT (π-center), linked by an electron D/D -or D/A pair segment; D-π-D (dye 1) or D-π-A (dye 2), to develop efficient bipolar light-emitting (LE) materials capable of balanced electron/hole capture in a single-layer LE device. A strong bipolarity manifested by electrochemical amphotericity was observed notably with dye 1, which cannot be accounted for without the involvement of the n-center, leading to the low HOMO/LUMO energy-gap and a small difference in the energy-gap between dye 1 and dye 2. Single-layer LE devices were fabricated by making a blend based on the dye (0.5 wt%), PVK (70%) as matrix and PBD (30%) as electron-transporting/hole blocking material, and by sandwiching between ITO and Al electrodes. PL intensity of the dyes by excitation at 440-450 nm (λmax) is much weaker compared to that at 340 nm (exciting mainly PVK), suggesting that the excitation of the dyes occur by energy-transfer from PVK. When compared PL intensities between the two dyes at a concentration <1%, dye 1 is slightly higher relative to dye 2. In contrast, the EL intensity shows an opposite trend in that dye 2 is much higher relative to dye 1 under the same condition. This implies that unlike the PL, the EL is not due to the transfer of the excited-energy from PVK but carrier trapping/exciton formation on the dye chromophore, and that dye 2 is strongly bipolar and thus more capable of balanced carrier capture.

Original languageEnglish
Pages (from-to)134-140
Number of pages7
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume3955
Publication statusPublished - 2000 Jan 1
Externally publishedYes
EventLiquid Crystal Materials, Devices and Flat Panel Displays - San Jose, CA, USA
Duration: 2000 Jan 272000 Jan 28

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ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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