Processes for high efficiency of organic EL devices with dopants

Masaki Yamaguchi, Takao Nagatomo

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Perylene doped poly(9-vinylcarbazole) (PVCz) was used as a light-emitting layer. The difference between the lowest unoccupied molecular orbital (LUMO) of PVCz and the Fermi level of MgAg cathode is 1.9 eV. Therefore, to decrease this potential difference, 2(4′-tert-butylphenyl)-5-(4′-biphenyl)-1,3,4-oxiadiazole (Bu-PBD) and tris(8-hydroxyquinoline) aluminum (AlQ) layers were inserted between PVCz and MgAg cathode. The copper phthalocyanine (CuPc) layer decreases the barrier height between the Fermi level of ITO anode and the highest occupied molecular orbital (HOMO) of PVCz. These electroluminescence (EL) devices have a wide range luminescent spectral from blue to yellow/green colors by varying doping levels of perylene into PVCz. It was clarified that the luminance and efficiency can be improved by the EL cell structure. Our experimental evidence indicates that the dopant concentration and carrier injection balance have an influence on obtaining high luminance and efficiency.

Original languageEnglish
Pages (from-to)21-24
Number of pages4
JournalThin Solid Films
Volume363
Issue number1
DOIs
Publication statusPublished - 2000 Mar 1

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ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Condensed Matter Physics
  • Surfaces and Interfaces

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