Patent ID: 8722208

Claim:
An organic electroluminescent device constituted of an anode, organic layers comprising a phosphorescent light-emitting layer, and a cathode piled one upon another on a substrate wherein at least one layer selected from the group consisting of a phosphorescent light-emitting layer, an electron-transporting layer, a hole-blocking layer, and an exciton-blocking layer comprises a phosphine oxide derivative represented by general formula (1): wherein L 1 is independently a direct bond or an aromatic group with a valence of 1-3 formed by removing 1-3 hydrogen atoms from an aromatic compound represented by the following formula (1a), (1b), or (1c) and at least one of L 1 s is not a direct bond; Ar 1 is independently an aromatic hydrocarbon group of 6-20 carbon atoms or an aromatic heterocyclic group of 3-20 carbon atoms and the two Ar 1 groups linked to the same nitrogen atom may join together directly or through another atom to form a nitrogen heterocycle and may further form a fused ring together with the said nitrogen heterocycle; the aforementioned aromatic hydrocarbon group or aromatic heterocyclic group may have substituents; m, n, and p each is independently an integer of 0-2 and m+n+p is 1-6; in formula (1a), (1b), or (1c), X is independently a substituted or unsubstituted methine group or nitrogen and, when L 1 is a divalent or trivalent aromatic group, at least one of Xs is nitrogen; when X is a substituted methine group, the substituent therein is independently an alkyl group of 1-6 carbon atoms, an alkoxyl group of 1-6 carbon atoms, an aryloxyl group of 3-20 carbon atoms, an aromatic hydrocarbon group of 6-20 carbon atoms, or an aromatic heterocyclic group of 3-20 carbon atoms: