Bipolar conductive vinyl copolymers for homojunction and heterojunction OLED applications

Louis M L LEUNG, Yik Chung Law, Michael Y. Wong, T. H. Lee, K. M. Lai, Lok Yee Tang

Research output: Contribution to conferencePaperpeer-review

1 Citation (Scopus)

Abstract

In this presentation, we shall report the synthesis and characterization of two series of conductive vinyl copolymers. The conductive vinyl copolymers all have high molecular weight (MW) and excellent thin film forming capability yet remain soluble in a range of organic solvents. Properties such as MW, Tg/Td (glass transition and degradation temperature), LUMO/HOMO, absorption/emission spectra, and devices properties for homo- and heterojunction devices based on the copolymers were determined. The first series is a copolymer of the hole transporting monomer N-(4-methoxyphenyl)- N-(4-vinylphenyl)naphthalen-1-amine (MeONPA) and an electron transporting 2-phenyl-5-(4-vinylphenyl)-1,3,4- oxadiazole (OXA). Charge balanced heterojunction charge balanced OLEDs using these hole-limiting (NPA/OXA) copolymers with Alq3 were prepared. A maximum luminance of over 23,000 cd/m2 and efficiency at 4.2 cd/A was resulted at an optimum copolymer composition. Suppression on the degradation of the Alq3 layer due to formation of cationic Alq3 species was detected. The second is a copolymer series of the hole transporting N-(4-methoxyphenyl)-N-(4-vinylphenyl)naphthalen- 1-amine (MeONPA) and electron transporting 1-vinyl-pyrene (py). Formation of exciplexes due to pi-pi staggered of the pyrene moieties led to a bluish green emission for poly(1-vinylpyrene). Random copolymers of pyrene with another non-planar monomer (MeONPA) suppressed exciplexes formation and the devices emitted from blue (460 nm) to bluish green (500 nm) color pending on the copolymer composition. Homojunction devices for these copolymers achieved highest luminance at 2,270 cd/m2 and an efficiency of 1.32 cd/A.

Original languageEnglish
Publication statusPublished - 2009
Event2009 International Display Manufacturing Conference, 3D Systems and Applications, and Asia Display, IDMC/3DSA/Asia Display 2009 - Taipei, Taiwan, Province of China
Duration: 27 Apr 200930 Apr 2009

Conference

Conference2009 International Display Manufacturing Conference, 3D Systems and Applications, and Asia Display, IDMC/3DSA/Asia Display 2009
Country/TerritoryTaiwan, Province of China
CityTaipei
Period27/04/0930/04/09

Scopus Subject Areas

  • Computer Graphics and Computer-Aided Design
  • Computer Science Applications
  • Human-Computer Interaction

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