White light-emitting OLED device having a blue light-emitting layer doped with an electron-transporting or a hole-transporting material or both

1. An organic light-emitting diode (OLED) device which produces white light, comprising:

a) an anode;

b) a hole-transporting layer disposed over the anode;

c) a blue light-emitting layer having a host doped with a blue light-emitting compound disposed directly on the hole-transporting layer and the blue light-emitting layer being doped with an electron-transporting or a hole-transporting material or both selected to improve efficiency and operational stability;

d) an electron-transporting layer disposed over the blue light-emitting layer;

e) a cathode disposed over the electron-transporting layer; and

f) the hole-transporting layer or electron-transporting layer, or both the hole-transporting layer and electron-transporting layer, being selectively doped with a compound which emits light in the yellow region of the spectrum which is included in an entire layer or a partial portion of a layer in contact with the blue light-emitting layer.

2. The OLED device of claim 1 wherein hole-transporting or the electron-transporting material in the blue light-emitting layer is selected to be in a range of from 0.5 to 10 percent by volume of the host material and when both are used, they are selected to be in a range of from 1 to 20 percent by volume of the host material.

3. The OLED device of claim 1 wherein the hole-transporting material in the blue light-emitting layer is:

1,1-Bis(4-di-p-tolylaminophenyl)cyclohexane;

1,1-Bis(4-di-p-tolylaminophenyl)-4-phenylcyclohexane;

4,4′-Bis(diphenylamino)quadriphenyl;

Bis(4-dimethylamino-2-methylphenyl)-phenylmethane;

N,N,N-Tri(p-tolyl)amine;

4-(di-p-tolylamino)-4′-[4(di-p-tolylamino)-styryl]stilbene;

N,N,N′,N′-Tetra-p-tolyl-4-4′-diaminobiphenyl;

N,N,N′,N′-Tetraphenyl-4,4′-diaminobiphenyl;

N,N,N′,N′-tetra-1-naphthyl-4,4′-diaminobiphenyl;

N,N,N′,N′-tetra-2-naphthyl-4,4′-diaminobiphenyl; N-Phenylcarbazole;

4,4′-Bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB);

4,4′-Bis[N-(1-naphthyl)-N-(2-naphthyl)amino]biphenyl (TNB);

4,4″-Bis[N-(1-naphthyl)-N-phenylamino]p-terphenyl;

4,4′-Bis[N-(2-naphthyl)-N-phenylamino]biphenyl;

4,4′-Bis[N-(3-acenaphthenyl)-N-phenylamino]biphenyl;

1,5-Bis[N-(1-naphthyl)-N-phenylamino]naphthalene;

4,4′-Bis[N-(9-anthryl)-N-phenylamino]biphenyl;

4,4″-Bis[N-(1-anthryl)-N-phenylamino]-p-terphenyl;

4,4′-Bis[N-(2-phenanthryl)-N-phenylamino]biphenyl;

4,4′-Bis[N-(8-fluoranthenyl)-N-phenylamino]biphenyl;

4,4′-Bis[N-(2-pyrenyl)-N-phenylamino]biphenyl;

4,4′-Bis[N-(2-naphthacenyl)-N-phenylamino]biphenyl;

4,4′-Bis[N-(2-perylenyl)-N-phenylamino]biphenyl;

4,4′-Bis[N-(1-coronenyl)-N-phenylamino]biphenyl;

2,6-Bis(di-p-tolylamino)naphthalene;

2,6-Bis[di-(1-naphthyl)amino]naphthalene;

2,6-Bis[N-(1-naphthyl)-N-(2-naphthyl)amino]naphthalene;

N,N,N′,N′-Tetra(2-naphthyl)- 4,4″-diamino-p-terphenyl;

4,4′-Bis{N-phenyl-N-[4-(1-naphthyl)-phenyl]amino}biphenyl;

4,4′-Bis[N-phenyl-N-(2-pyrenyl)amino]biphenyl;

2,6-Bis[N,N-di(2-naphthyl)amine]fluorene;

1,5-Bis[N-(1-naphthyl)-N-phenylamino]naphthalene;

4,4′,4″-tris[(3-methylphenyl)phenylamino]triphenylamine (MTDATA); or

4,4′-Bis[N-(3-methylphenyl)-N-phenylamino]biphenyl (TPD).

4. The OLED device of claim 1 wherein the electron-transporting materials in the blue light-emitting layer is:

BAlq;

Aluminum trisoxine [alias, tris(8-quinolinolato)aluminum(III)];

Magnesium bisoxine [alias, bis(8-quinolinolato)magnesium(II)];

Bis[benzo{f}-8-quinolinolato]zinc (II);

Bis(2-methyl-8-quinolinolato)aluminum(III)-μ-oxo-bis(2-methyl-8-quinolinolato) aluminum(III);

Indium trisoxine [alias, tris(8-quinolinolato)indium];

Aluminum tris(5-methyloxine) [alias, tris(5-methyl-8-quinolinolato) aluminum(III)];

Lithium oxine [alias, (8-quinolinolato)lithium(I)];

Gallium oxine [alias, tris(8-quinolinolato)gallium(III)]; or

Zirconium oxine [alias, tetra(8-quinolinolato)zirconium(IV)].

5. The OLED device of claim 1 wherein the hole-transporting material is NPB and the electron-transporting material is Alq.

6. The OLED device of claim 1 wherein the hole-transporting material is NPB and the electron-transporting material is BAlq.

7. The OLED device of claim 1 wherein the yellow light-emitting compound is:

wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 represent one or more substituents on each ring where each substituent is individually selected from the following groups:

Group 1: hydrogen, or alkyl of from 1 to 24 carbon atoms;

Group 2: aryl or substituted aryl of from 5 to 20 carbon atoms;

Group 3: carbon atoms from 4 to 24 necessary to complete a fused aromatic ring of phenyl, naphthyl, anthracenyl, phenanthryl, pyrenyl, or perylenyl;

Group 4: heteroaryl or substituted heteroaryl of from 5 to 24 carbon atoms such as thiazolyl, furyl, thienyl, pyridyl, quinolinyl or other heterocyclic systems, which may be bonded via a single bond, or may complete a fused heteroaromatic ring system;

Group 5: alkoxylamino, alkylamino, or arylamino of from 1 to 24 carbon atoms; or

Group 6: fluorine, chlorine, bromine or cyano.

8. The OLED device of claim 6 wherein the yellow-emitting dopants includes 5,6,11,12-tetraphenylnaphthacene (rubrene); 6,11-diphenyl-5,12-bis(4-(6-methyl-benzothiazol-2-yl)phenyl)naphthacene (DBzR) or 5,6,11,12-tetra(2-naphthyl)naphthacene (NR), the formulas of which are shown below:

9. The OLED device of claim 1 wherein the blue light emitting compound includes distyrylamine derivatives as shown by the formula

10. The OLED device of claim 1 wherein the blue emitting compound dopant further includes perylene and its derivatives.

11. The OLED device of claim 10 wherein the perylene derivative is 2,5,8,11-tetra-tert-butyl perylene (TBP).

12. The OLED device of claim 1 wherein the blue light emitting compound is represented by the following formulas:

13. The OLED device of claim 1 wherein the concentration of blue emitting dopants, is in the range of greater than 0 and less than 10% percent by volume of the host material.

14. The OLED device of claim 1 wherein thickness of the hole-transporting layer is between 5 nm-300 nm.

15. The OLED device of claim 1 wherein the hole-transporting layer includes two or more sublayers, the sublayer closest to the blue light-emitting layer being doped with yellow-emitting dopants.

16. The OLED device of claim 15 wherein the dopant in the hole transport material is 5,6,11,12-tetraphenylnaphthacene (rubrene); 6,11-diphenyl-5, 12-bis(4-(6-methyl-benzothiazol-2-yl)phenyl)naphthacene (DBzR); or 5,6,11,12-tetra(2-naphthyl)naphthacene (NR), and the thickness of the layer containing yellow dopant is in a range between 1 nm-300 nm.

17. The OLED device of claim 1 wherein thickness of the blue light-emitting layer is in a range between 5 nm-100 nm.

18. The OLED device of claim 1 wherein a hole-injecting layer is provided between the anode and the hole-transporting layer.

19. The OLED device of claim 18 wherein the hole-injecting layer comprises CFx, CuPC, or m-MTDATA.

20. The OLED device of claim 18 wherein the thickness of hole injecting layer is 0.1 nm-100 nm.

21. The OLED device of claim 1 wherein thickness of the electron-transporting layer is in a range between 5 nm-150 nm.

22. The OLED device of claim 1 wherein the cathode is selected from the group consisting of LiF/Al, Mg:Ag alloy, Al—Li alloy, and Mg—Al alloy.

23. The OLED device of claim 1 wherein the cathode is transparent.

24. The OLED device of claim 1 wherein the electron-transporting layer is transparent.

25. The organic light-emitting diode (OLED) device of claim 1 wherein the electron-transporting layer is doped with a green light-emitting dopant or a combination of green and yellow light-emitting dopants.

26. The OLED device of claim 25 wherein of the green dopant in the electron-transporting layer includes a coumarin compound.

27. The OLED device of claim 26 wherein the coumarin compound includes C545T or C545TB.

28. The OLED device of claim 25 wherein the green light-emitting dopant is selected from the group consisting of:

29. The OLED device of claim 25 wherein green dopant concentration is between 0.1-5% percent by volume of the electron transport material in the electron transporting layer.

30. The OLED device of claim 1 further including a buffer layer disposed on the cathode layer.

31. The OLED device of claim 30 wherein thickness of the buffer layer is in a range between 1 nm-1000 nm.

32. The OLED device of claim 1 further including a color filter array.

33. The OLED device of claim 1 wherein the hole-transporting layer includes an aromatic tertiary amine.

34. The OLED device of claim 1 wherein the electron-transporting layer includes copper phthalocyanine compound.

35. The OLED device of claim 1 wherein the blue light-emitting layer includes host material selected from the group consisting of:

and wherein the blue light-emitting dopant includes

or derivatives thereof.

36. The OLED device of claim 3 wherein the blue light-emitting layer includes host material selected from the group consisting of:

and wherein the blue light-emitting dopant includes

or derivatives thereof.