Synthesis and properties of PCPP-based conjugated polymers containing pendant carbazole units for LEDs

Youngeup Jin, Hee Kim Sun, Hyojin Lee, Suhee Song, Yunna Kim, Han Young Woo, Kwanghee Lee, Hongsuk Suh

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Abstract

New poly(cyclopenta[def]phenanthrene) (PCPP)-based conjugated copolymers, containing carbazole units as pendants, were prepared as the electroluminescent (EL) layer in light-emitting diodes (LEDs) to show that most of them have higher maximum brightness and EL efficiency. The prepared polymers, Poly(2,6-(4-(6-(Ncarbazolyl)-hexyl)-4-octyl-4H-cyclopenta[def]phenanthrene)) (CzPCPP10) and Poly(2,6-(4-(6-(N-carbazolyl)-hexyl)-4-octyl-4H-cyclopenta[def] phenanthrene))-co-(2,6-(4,4-dioctyl-4H-cyclopenta[def]phenanthrene)) (CzPCPP7 and CzPCPP5), were soluble in common organic solvents and used as the EL layer in light-emitting diodes (LEDs) of configuration with ITO/PEDOT/polymer/Ca/Al device. The polymers are thermally stable with glass transition temperature (Tg) at 77-100 °C and decomposition temperature (Td) at 423-457 °C. The studies of cyclic voltammetry indicated same HOME levels in all polymers, although the ratios of carbazole units are different. In case of PLEDs with configuration of ITO/PEDOT/CzPCPPs/Ca/Al device, The EL maximum peaks were around 450 nm, which the turn-on voltages were about 6.0-6.5 V. The maximum luminescence of PLEDs using CzPCPP10 was over 4400 cd/m2 at 6.5 V, which all of the maximum EL efficiency were 0.12 cd/A. The CIE coordinates of the EL spectrum of PLEDs using CzPCPP10 was (0.18, 0.08), which are quite close to that of the standard blue (0.14, 0.08) of NTSC.

Original languageEnglish
Pages (from-to)2419-2425
Number of pages7
JournalBulletin of the Korean Chemical Society
Volume28
Issue number12
DOIs
Publication statusPublished - 2007 Dec 20
Externally publishedYes

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Keywords

  • Carbazole
  • Light emitting diode
  • PCPP

ASJC Scopus subject areas

  • Chemistry(all)

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