OLED device with hole-transport and electron-transport materials

1. An OLED device comprising, in the following order, an anode, a hole transporting layer (HTL), a light-emitting layer (LEL) comprising a host molecule and a light-emitting molecule, an electron transporting layer (ETL) and a cathode and wherein:

(i) the HTL comprises a hole transporting material (HTM) having an oxidation potential that is at least 0.2 V less positive than the oxidation potential of a predominant material in the ETL and does not contain any bonds having an energy less than 105 kcal/mol; and

(ii) the ETL comprises an electron transporting material (ETM) having a reduction potential (RP etm ) relative to the reduction potential of a predominant material in the HTL (RP htm ) that meets the requirement of RP etm >(RP htm −0.05).

2. The OLED device of claim 1 wherein the oxidation potential of the HTM is at least 0.3 V less positive than the oxidation potential of the predominant material in the ETL.

3. The OLED device of claim 1 wherein the reduction potential of the ETM is more positive than the reduction potential of the predominant material in the HTL.

4. The OLED device of claim 1 where the HTM is an anthracene compound.

5. The OLED device of claim 4 wherein the anthracene compound is according to Formula (P):

wherein

R 1 -R 10 are independently chosen from hydrogen or aromatic groups from 1-24 carbon atoms.

6. The OLED device of claim 1 wherein the ETM is a fluoranthene compound.

7. The OLED device of claim 6 wherein the fluoranthene compound is according to the Formula (I):

wherein

each Ar is an aromatic ring containing 6 to 24 carbon atoms bonded to the fluoranthene nucleus and they can be are the same or different; and

R 1 -R 8 are individually selected from hydrogen and aromatic ring groups containing 6 to 24 carbon atoms with the proviso that no two adjacent R 1 -R 8 substituents can join to form an aromatic ring system fused to the fluoranthene nucleus.

8. The OLED device of claim 1 wherein the ETM is a phenanthroline compound.

9. The OLED device of claim 8 wherein the phenathroline compound is according to the Formula (R):

wherein

R 1 -R 8 are independently hydrogen, alkyl group, aryl or substituted aryl group, and at least one of R 1 -R 8 is aryl group or substituted aryl group.

10. The OLED device of claim 1 wherein the ETM is according to Formula (G a ):

GaL 3   (G a )

wherein:

the gallium is in a +3 valence state; and

L represent a monoionic ligand such that the complex has an overall neutral charge, each L may be the same or different and at least one L must be organic.

11. The OLED device of claim 10 wherein the gallium complex is according to Formula (G a -1):

wherein:

each Z a and Z b is independently selected and represents the atoms necessary to complete an unsaturated heterocyclic ring and each heterocyclic ligand can be the same or different.

12. The OLED of claim 1 wherein the electron transporting layer is in direct contact with the light-emitting layer.

13. The OLED of claim 1 wherein the light-emitting layer emits blue light.

14. The OLED of claim 13 wherein the light-emitting molecule is chosen from the group consisting of bis(azinyl)azene boron complex compounds, bis[2-[4-[N,N-diarylamino]phenyl]vinyl]-benzenes, [N,N-diarylamino][2-[4-[N,N- diarylamino]phenyl]vinyl]biphenyls and bis[2-[4-[N,N-diarylamino]phenyl]vinyl]biphenyls.

15. The OLED of claim 14 wherein the HTM is an anthracene compound.

16. The OLED of claim 1 wherein the HTM has an oxidation potential of 1.50 V or less and a reduction potential of −1.70 V or more negative.

17. The OLED of claim 16 wherein the HTM has an oxidation potential of less than 1.35 V and a reduction potential more negative than −1.80 V.

18. The OLED of claim 1 wherein the ETM has an oxidation potential of 1.50 V or greater and a reduction potential of −1.95 V or less negative.

19. A method of emitting light comprising applying an electric potential across the device of claim 1 .

20. A display comprising the device of claim 1 .