Organic phosphorescent light emitting device

1. An OLED device comprising a cathode, an anode, and located therebetween a light emitting layer containing a host compound, and further containing a light-emitting dopant compound represented by formula (I):

wherein

M is Iridium;

the coordination ring C is a triazole ring with the metal as a member of the triazole ring;

A is a five- or six-membered heteroaryl ring comprising at least two nitrogen atoms and is optionally substituted and optionally fused to one or more other aryl or heteroaryl rings;

B is a five membered heteroaryl ring substituted to contain fused ring D as represented by formula (III):

wherein:

ring D is an aryl or heteroaryl ring; R 6 is selected from alkyl, alkenyl, alkoxy, aryl, aralkyl, halogen, NH 2 , NHR, NR 2 , NO 2 , CN, C(O)OR, C(O)R, C(O)NR, P(O)RR′, P(S)RR′, SO 2 , SOR, SO 2 R, SO 3 R, BRR′, and B(OR) 2 groups wherein each R or R′ is independently selected from alkyl, alkenyl, alkynyl, aralkyl, and aryl groups; ring D may be optionally fused to one or more other aryl or heteroaryl rings and n is zero or an integer equal to or greater than one;

R 1 and R 2 are groups other than hydrogen and may be joined together;

n 1 and n 2 are independently an integer from 0 to 6;

L is a ligand and at least one L is 2-phenylpyridine or phenylpyrazole, wherein the phenylpyridine or phenylpyrazole ligand optionally is substituted with one or more alkyl, alkenyl, alkynyl, alkylaryl, CN, CF 3 , COOR, C(O)R, NR 2 , NO 2 , OR, aryl, heteroaryl, substituted aryl, substituted heteroaryl or a heterocyclic group, and additionally, any two adjacent substituted positions together may form, independently, a fused 5- to 6-membered cyclic group, wherein said cyclic group is cycloalkyl, cycloheteroalkyl, aryl, or heteroaryl; and wherein the fused 5- to 6-membered cyclic group may be optionally substituted with one or more alkyl, alkenyl, alkynyl, alkylaryl, CN, CF 3 , COOR, C(O)R, NR 2 , NO 2 , OR or halo; wherein each R is independently selected from alkyl, alkenyl, alkynyl, aralkyl, and aryl;

n 3 is zero or an integer;

and n 4 is an integer of at least one.

2. The device of claim 1 wherein ring A is represented by formula (II):

wherein:

R 3 , R 4 and R 5 are selected from alkyl, alkenyl, alkoxy, aryl, aralkyl, halogen, NH 2 , NHR, NR 2 , NO 2 , CN, C(O)OR, C(O)R, C(O)NR, P(O)RR′, P(S)RR′, SO 2 , SOR, SO 2 R, SO 3 R, BRR′, and B(OR) 2 wherein each R or R′ is independently selected from alkyl, alkenyl, alkynyl, aralkyl, and aryl.

3. The device of claim 1 wherein the dopant compound is a homoleptic compound.

4. The device of claim 1 wherein the dopant compound is a heteroleptic compound.

5. The device of claim 1 wherein the dopant compound is represented by formula (IV):

wherein:

M is Ir;

R 1 and R 2 are groups other than hydrogen;

n 1 and n 2 are independently an integer from 0 to 6;

L is a ligand and at least one L is 2-phenylpyridine or phenylpyrazole, wherein the phenylpyridine or phenylpyrazole ligand optionally is substituted with one or more alkyl, alkenyl, alkynyl, alkylaryl, CN , CF 3 , COOR, C(O)R, NR 2 , NO 2 , OR, aryl, heteroaryl, substituted aryl, substituted heteroaryl or a heterocyclic group, and additionally, any two adjacent substituted positions together may form, independently, a fused 5- to 6-membered cyclic group, wherein said cyclic group is cycloalkyl, cycloheteroalkyl, aryl, or heteroaryl; and wherein the fused 5- to 6-membered cyclic group my be optionally substituted whit one or more alkyl, alkenyl, alkynyl, alkylaryl, CN, CF 3 , COOR, C(O)R, NR 2 , NO 2 , OR or halo; wherein each R is independently selected from alkyl, alkenyl, alkynyl, aralkyl, and aryl;

n 3 is 0 or an integer up to 3

and n 4 is an integer from 1 to 3.

6. The device of claim 5 wherein the compound is a homoleptic compound.

7. The device of claim 5 wherein n 3 is an integer from 1 to 3.

8. The device of claim 1 wherein the light emitting layer contains at least two host materials.

9. The device of claim 1 wherein the device additionally contains an electron transport layer wherein the electron transport layer contains a combination of two or more materials.