Bright blue organic light-emitting diode with improved color purity using a LiF/Al cathode

S. E. Shaheen, G. E. Jabbour, M. M. Morrell, Y. Kawabe, B. Kippelen, N. Peyghambarian, M. F. Nabor, R. Schlaf, E. A. Mash, N. R. Armstrong

Research output: Contribution to journalArticle

288 Scopus citations

Abstract

We report a two-layer, blue organic light-emitting diode with a 4,4′-bis(2,2-diphenylvinyl)-1,1′ -biphenyl emission layer and a LiF/Al cathode which has an external quantum efficiency of 1.4% and a maximum luminance of 3000 cd/m2. Insertion of the thin LiF layer results in a 50-fold increase in the device efficiency compared to a device with an aluminum only cathode, and eliminates the need for an electron-transporting layer, such as tris(8-hydroxyquinoline)aluminum. This results in a device with excellent color purity with an emission peak at 476 nm and a full width at half maximum of 78 nm. Using ultraviolet photoelectron spectroscopy, we find that the effective work-function of aluminum decreases dramatically with sub-monolayer amounts of LiF deposited on the surface.

Original languageEnglish (US)
Pages (from-to)2324-2327
Number of pages4
JournalJournal of Applied Physics
Volume84
Issue number4
DOIs
StatePublished - Aug 15 1998

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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