Blue emitting internal junction organic electroluminescent device (II)

Abstract

An internal junction organic electroluminescent device is disclosed comprised of, in sequence, an anode, an organic hole injecting and transporting zone, an organic electron injecting and transporting zone, and a cathode. The organic electron injecting and transporting zone is comprised of an electron injecting layer in contact with the cathode and, interposed between the electron injecting layer and the organic hole injecting and transporting zone, a blue emitting luminescent layer comprised of an aluminum chelate containing a phenolato ligand and two R.sup.S -8-quinolinolato ligands, where R.sup.S substitutents are chosen to block the attachment of more than two substituted 8-quinolinolato ligands to the aluminum atom. The presence of the phenolato ligand shifts device emission to the blue region of the spectrum and increases emission efficiency. Device emission is shifted to even shorter blue wavelengths and increased operating stability can be realized by the incorporation of a pentacarbocyclic aromatic fluorescent dye.

Dependencies are inferred from the claim text.