A composition is provided containing a phosphorescent compound and a polymer compound having a constitutional unit represented by the formula (Y):

Ar.sup.Y1(Y)

wherein Ar.sup.Y1 represents an arylene group, a divalent heterocyclic group or the like; and at least one constitutional unit selected from the constitutional units represented by the formulas (Ia) to (Id):

##STR00001##

wherein m represents an integer of 0 to 4, n represents an integer of 0 to 3, R.sup.T1 represents an alkyl group, an alkoxy group, an aryl group, a monovalent heterocyclic group or the like, R.sup.x represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, a monovalent heterocyclic group or the like, Ar represents an aromatic hydrocarbon group or a heterocyclic group, nA and nB represent an integer of 0 to 3, and L.sup.A and L.sup.B represent an alkylene group, a cycloalkylene group, an arylene group or a divalent heterocyclic group.

It is an object of the present invention to provide a composition using a polymer compound, which is useful for manufacturing a blue phosphorescent light-emitting device excellent in luminous efficiency. The present invention provides a composition including: a polymer compound substantially consisting of a constitutional unit selected from a constitutional unit represented by Formula (1)-1 below, a constitutional unit represented by Formula (1)-2 below, a constitutional unit represented by Formula (2)-1 below, a constitutional unit represented by Formula (2)-2 below, and a constitutional unit derived from a phosphorescent light-emitting compound having a light-emitting spectrum peak at smaller than 480 nm and the polymer compound containing at least both of the constitutional unit represented by Formula (1)-1 and the constitutional unit represented by Formula (1)-2; and a phosphorescent light-emitting compound having a light-emitting spectrum peak at smaller than 480 nm. ##STR00001##

A method of forming a polymer comprising a conjugated backbone and side-groups pendant from the conjugated backbone wherein the method comprises the steps of: polymerising one or more monomers to form a precursor polymer comprising the conjugated backbone and precursor groups pendant from the conjugated backbone, and subsequently converting the precursor groups to the side-groups.

The present invention relates to a mixture comprising a) a polymer which contains at least one L=X structural unit, b) a triplet emitter compound and c) a carbazole compound or a soluble neutral molecule. The invention furthermore relates to organic electroluminescent devices which contain the mixture according to the invention.

An organic light-emitting device comprising an anode (103); a cathode (109); a light-emitting layer (105) between the anode and the cathode; and an electron-transporting layer (107) comprising an electron-transporting material between the cathode and the light-emitting layer, wherein the cathode comprises a layer of a conducting material (109B) and a layer of an alkali metal compound (109A) between the electron-transporting layer and the layer of conducting material and wherein the electron-transporting material is a conjugated polymer comprising arylene repeat units.

A composition is provided containing: a phosphorescent compound having an emission spectrum whose maximum peak wavelength is between 380 nm or more and less than 495 nm, having no dendron and represented by formula (1); two or more phosphorescent compounds having an emission spectrum whose maximum peak wavelength is between 495 nm or more and less than 750 nm and having a dendron; and a compound represented by formula (H-1).

##STR00001##

In formula (1) M represents an iridium atom or the like, n.sup.1 represents an integer of 1 or more, n.sup.2 represents an integer of 0 or more, E.sup.1 and E.sup.2 represent a carbon atom or the like, the ring R.sup.1 represents a diazole ring, the ring R.sup.2 represents a 6-membered aromatic hydrocarbon ring or the like, and A.sup.1-G.sup.1-A.sup.2 represents an anionic bidentate ligand.

Provided is a light emitting device which is excellent in external quantum efficiency. The light emitting device comprises an anode, a cathode, a first light-emitting layer provided between the anode and the cathode, and a second light-emitting layer provided between the anode and the cathode. The first light-emitting layer is a layer obtained by using a polymer compound comprising a constitutional unit having a cross-linkable group and a phosphorescent constitutional unit, and the second light-emitting layer is a layer obtained by using a composition comprising a non-phosphorescent low molecular weight compound having a heterocyclic structure and at least two phosphorescent compounds.