Electroluminescent device
An electroluminescent device which has an electroluminescent layer formed of a binuclear, trinuclear or polynuclear rare earth organic complex in which the metals are linked through a bridging ligand.
1. An electroluminescent device comprising a first electrode, a second electrode, and a layer comprising an electroluminescent compound between the first electrode and the second electrode wherein:
the electroluminescent compound is selected from the group consisting of binuclear, trinuclear and polynuclear metal complexes in which nuclei are defined by at least two metal atoms, at least one of said metal atoms being selected from the group consisting of Sm (III), Eu (II), Eu (III), Tb (III), Dy(III), Yb (III), Lu (III), Gd (III), U(III), Tm (III), Ce (III), Pr (III), Nd (III), Pm (III), Dy (III), Ho (III), Er (III), and Yb (III), and at least a second of said metal atoms is selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, boron, aluminum, gallium, indium, germanium, tin, antimony, lead and metals of the first, second and third groups of transition metals;
further wherein each metal atom is linked to another metal atom through a bridging ligand, said bridging ligands each having the general chemical formula:
wherein: the groups R can be the same or different and are independently selected from the group consisting of hydrogen, substituted and unsubstituted aliphatic groups, substituted and unsubstituted aromatic, heterocyclic and polycyclic ring structures, fluorocarbon groups and halogen atoms; Ar represents a substituted or unsubstituted aromatic or heteroaromatic group; and
further wherein n is an integer from 1 to 10.
2. The device of claim 1 , wherein said at least one of said metal atoms is selected from the group consisting of Eu (III), Tb (III), Dy (III), and Gd(III).
3. The device of claim 1 , further comprising a layer of a hole transmitting material located between an electrode that serves as an anode and the electroluminescent layer.
4. The device of claim 3 , wherein the hole transmitting material is a film of a polymerized aromatic amine.
5. The device of claim 3 , wherein the hole transmitting material is a film comprising a material selected from the group consisting of poly (vinylcarbazole), N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD); polyaniline; substituted polyanilines; polythiophenes; substituted polythiophenes; polysilanes; and substituted polysilanes.
6. The device of claim 3 , wherein the hole transmitting material is an aromatic amine selected from the group consisting of the following compounds:
7. The device of claim 1 , further comprising a layer of an electron transmitting material located between an electrode that serves as a cathode and the electroluminescent material layer.
8. The device of claim 7 , wherein the electron transmitting material is a metal quinolate.
9. The device of claim 8 , wherein the metal quinolate is aluminium quinolate or lithium quinolate.
10. The device of claim 9 , wherein the electrode that serves as a cathode comprises a material selected from aluminium, calcium, lithium, and silver/magnesium alloys.
11. The device of claim 10 , wherein a lithium fluoride layer is formed on the electrode that serves as a cathode, said lithium fluoride layer being located between the cathode and the electron transmitting material.
12. The device of claim 1 , wherein each bridging ligand is selected from the group consisting of one of the following chemical formulas in which Ar represents a substituted or unsubstituted aromatic or heteromatic group: