Tandem white OLED with efficient electron transfer

1. A white-light-emitting tandem OLED device having spaced anode and cathode comprising:

a. first and second light-emitting units disposed between the cathode and anode;

b. an intermediate connector comprising an n-type layer and a p-type layer disposed between the first and second light-emitting units; and

c. a fluoranthene-containing electron-transporting layer adjacent to the n-type layer of the intermediate connector and comprising at least 25% of a 7,10-diaryl-substituted fluoranthene compound having no aromatic rings annulated to the fluoranthene nucleus.

2. The tandem OLED device of claim 1 wherein the n-type layer is a lithium-doped layer.

3. The tandem OLED device of claim 1 further including a second electron-transporting layer adjacent to the cathode and a second fluoranthene-containing electron-transporting layer adjacent to the second electron-transporting layer.

4. The tandem OLED device of claim 3 wherein the n-type layer, or the electron-transporting layer, or both are lithium-doped.

5. The tandem OLED of claim 1 wherein the fluoranthene compound is according to Formula (I):

wherein each Ar is an aromatic ring containing 6 to 24 carbon atoms bonded to the fluoranthene nucleus and they can be 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 annulated to the fluoranthene nucleus.

6. The tandem OLED device of claim 5 wherein the fluoranthene compound is according to Formula (II):

wherein:

R 1 , R 2 , R 3 and R 4 are independently hydrogen or an aromatic group containing 6 to 24 carbon atoms with the proviso that any adjacent R 1 -R 4 is not joined to form part of an annulated aromatic ring system; R is hydrogen or a substituent; and n and m are independently 1-5.

7. The tandem OLED device of claim 6 wherein the fluoranthene compound is according to Formula (III-a) or (III-b):

wherein:

R 2 and R 4 are independently hydrogen or an aromatic group containing 6 to 24 carbon atoms with the proviso that R 2 and R 4 cannot both be hydrogen nor can R 2 be joined with R to form a ring; and R is hydrogen or an optional substituent; and n and m are independently 1-5.

8. The tandem OLED device of claim 1 wherein one of the light-emitting units emits light in the blue region of the visible spectrum and the other light-emitting unit emits light in the red to green region of the visible spectrum.

9. The tandem OLED device of claim 1 further including a second electron-transporting layer adjacent to the cathode.

10. The tandem OLED device of claim 1 wherein each of the light-emitting units comprises a hole transporting layer.

11. The tandem OLED device of claim 1 further comprising a hole injection layer adjacent to the anode.

12. The tandem OLED device of claim 6 wherein at least one of the light-emitting units include an anthracene derivative having hydrocarbon or substituted hydrocarbon substituents at the 9 and 10 positions.

13. The tandem OLED device of claim 6 wherein the anthracene derivative is according to Formula B:

wherein R 1 , R 2 , R 3 , and R 4 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 anthracenyl, pyrenyl, or perylenyl;

Group 4: heteroaryl or substituted heteroaryl of from 5 to 24 carbon atoms as necessary to complete a fused heteroaromatic ring of furyl, thienyl, pyridyl, quinolinyl or other heterocyclic systems;

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

Group 6: fluorine, chlorine, bromine or cyano.

14. The tandem OLED device of claim 6 wherein the fluoranthene compound is according to any of Formulas ETM1-ETM21: