OLED with high efficiency blue light-emitting layer

1. An OLED device comprising:

an anode;

a cathode;

a light-emitting layer located therebetween, said light-emitting layer comprising an anthracene host and a styrylamine blue light-emitting compound; and

located between the said light-emitting layer and the cathode, a first electron-transporting layer that is greater than 0.5 nm and less than 5 nm thick and a second electron-transporting layer consisting essentially of an anthracene located between the first electron-transporting layer and the cathode;

wherein the first electron-transporting layer includes a compound with a less negative LUMO value than the anthracene in the second electron-transporting layer.

2. The OLED device of claim 1 wherein the difference in LUMO value between the compound in the first electron-transporting layer and the anthracene in the second electron-transporting layer is at least 0.26 eV.

3. The OLED device of claim 1 wherein the difference in LUMO value between the compound in the first electron-transporting layer and the anthracene in the second electron-transporting layer exceeds 0.35 eV.

4. The OLED device of claim 1 wherein the first electron-transporting layer is located in direct contact with the light-emitting layer.

5. The OLED device of claim 1 wherein the first electron-transporting layer additionally contains an anthracene.

6. The OLED device of claim 1 wherein there is an additional layer consisting essentially of an anthracene located between the first electron-transporting layer and the light-emitting layer.

7. The OLED device of claim 1 wherein the compound in the first electron-transporting layer is selected from benzene derivatives according to Formula (III):

wherein:

at least two of R 8 -R 11 both represent hydrogen or substituted carbon, silicon or nitrogen atoms with the proviso that no more than two of R 8 -R 11 are hydrogen.

8. The OLED device of claim 7 wherein the benzene derivative is selected from the group consisting of

9. The OLED device of claim 1 wherein the compound in the first electron-transporting layer is a naphthalene derivative according to Formula (IV)

wherein:

R 12 is an aromatic substituent and p is 2 to 8.

10. The OLED device of claim 9 wherein the naphthalene derivative is:

11. The OLED device of claim 1 wherein the compound in the first electron-transporting layer is an iridium derivative according to Formula (V):

wherein:

M is iridium;

A is a substituted or unsubstituted heterocyclic ring containing at least one nitrogen atom;

B is a substituted or unsubstituted aromatic or heteroaromatic ring, or ring containing a vinyl or aromatic carbon bonded to M;

X-Y is an anionic bidentate ligand; m is an integer from 1 to 3 and

n in an integer from 0 to 2 such that m+n=3.

12. The OLED device of claim 11 wherein the iridium derivative is tris(2-phenyl-pyridinato-N,C 2 -)iridium (III).

13. The OLED device of claim 1 wherein the anthracene in the second electron-transporting layer is according to formula (I):

wherein:

R 1 and R 6 each independently represent an aryl group having 6-24 carbon atoms; R 2 -R 5 and R 7 -R 10 are each independently chosen from hydrogen, alkyl groups from 1-24 carbon atoms, or aromatic groups from 5-24 carbon atoms.

14. The OLED device of claim 6 wherein the anthracene in the additional layer is according to formula (I):

wherein:

R 1 and R 6 each independently represent an aryl group having 6-24 carbon atoms; R 2 -R 5 and R 7 -R 10 are each independently chosen from hydrogen, alkyl groups from 1-24 carbon atoms, or aromatic groups from 5-24 carbon atoms.

15. The OLED device of claim 14 wherein the anthracenes in both the second electron-transporting layer and the additional layer are the same.

16. The OLED device of claim 1 wherein the anthracene host in the light-emitting layer is according to Formula (I):

wherein:

R 1 and R 6 each independently represent an aryl group having 6-24 carbon atoms; R 2 -R 5 and R 7 -R 10 are each independently chosen from hydrogen, alkyl groups from 1-24 carbon atoms, or aromatic groups from 5-24 carbon atoms.

17. The OLED device of claim 1 wherein the styrylamine blue light-emitting compound is according to formula (II):

wherein:

R 1 , R 2 , R 3 and R 4 are independently chosen aryl groups of 6-24 nucleus carbon atoms with the proviso that R 1 and R 2 or R 3 and R 4 can be joined together to form a ring; or alkyl groups of 1-6 carbon atoms;

R 5 is selected from alkyl and aryl groups;

n is 0-4;

R 6 and R 7 are independently selected from hydrogen, alkyl or aryl groups; and

Ar represents a substituted or unsubstituted aryl group of 6 to 30 nucleus carbon atoms.