Organic element for electroluminescent devices
View Patent ↗Disclosed is an OLED device comprising a light-emitting layer (LEL) containing a host and a dopant located between a cathode and an anode wherein the emitter is an orange-red light emitting rubrene derivative represented by formula (I): wherein: a) there are identical aromatic groups at the 2- and 8-positions; b) the phenyl rings in the 5- and 11-positions contain only para-substituents identical to the aromatic groups in paragraph a); and c) the phenyl rings in the 6- and 12-positions are substituted or not.
1. An OLED device comprising a light-emitting layer (LEL) containing a host and an emitting dopant located between a cathode and an anode wherein the dopant is an orange-red light emitting rubrene derivative represented by formula (I):
wherein:
a) there are identical aromatic groups at the 2- and 8-positions;
b) the phenyl rings in the 5- and 11-positions contain only para-substituents identical to the aromatic groups in paragraph a); and
c) the phenyl rings in the 6- and 12-positions are substituted or not in which formula (I) is represented by formula (II):
wherein
R 1 is an aromatic carbocyclic or heterocyclic group;
R 2 is a substituent group;
n is 0–5;
provided that all R 1 are the same; and
provided further, that the R 2 , their location and n value on one ring are the same as those on the second ring.
2. The device of claim 1 comprising a further light-emitting compound to provide a white light emission.
3. The device of claim 2 further comprising a blue light-emitting compound to provide a white light emission.
4. The device of claim 2 further comprising a filter over-lying the device.
5. The device of claim 2 wherein the layer comprises a host and dopant where the dopant is present in an amount of up to 10%-wt of the host.
6. The device of claim 5 wherein the dopant is present in an amount of 0.1–5.0 %-wt of the host.
7. The device of claim 1 wherein the dopant is represented by formula (III):
wherein
R 2 and R 3 are independently selected substituent groups;
n and m are independently 0–5;
provided that the R 2 , their location and n value on one ring are the same as those on the second ring; and
provided further, that the R 3 , their location and m value on one ring are the same as those on all rings containing R 3 .
8. The device of claim 7 wherein m is 0.
9. The device of claim 7 comprising a further light-emitting compound to provide a white light emission.
10. The device of claim 9 further comprising a blue light-emitting compound to provide a white light emission.
11. The device of claim 9 further comprising a filter over-lying the device.
12. The device of claim 1 wherein R 1 is a phenyl group.
13. The device of claim 1 wherein R 2 is located in the meta or para positions of the phenyl group.
14. The device of claim 1 wherein R 2 is fluorine.
15. The device of claim 1 wherein R 2 is a fluorine-containing group.
16. The device of claim 1 wherein the host is an amine compound.
17. The device of claim 1 wherein the host comprises N,N′-di-1-naphthalenyl-N,N′-diphenyl-4, 4′-diaminobiphenyl.
18. The device of claim 1 wherein the substituents are selected to provide a reduced loss of initial luminance compared to a device containing no rubrene derivative compound.
19. The device of claim 1 wherein R 2 are independently selected from the group consisting of fluorine, fluorine containing groups, alkyl, aryl, alkoxy and aryloxy groups.
20. The device of claim 1 wherein the dopant is present in an amount of up to 10%-wt of the host.
21. The device of claim 20 wherein the dopant is present in an amount of 0.1–5.0%-wt of the host.
22. The device of claim 1 wherein the rubrene derivative is selected from the following:
23. An OLED device of claim 1 wherein the rubrene derivative has a wavelength of maximum emission (λ max ) in ethyl acetate solution such that
560 nm<λ max ≦650 nm.
24. An OLED device of claim 23 wherein the rubrene derivative has a wavelength of maximum emission (λ max ) in ethyl acetate solution such that
565 nm<λ max ≦625 nm.
25. A light-emitting device containing the OLED device of claim 1 .
26. A light-emitting display containing the OLED device of claim 1 .
27. A method of emitting light comprising subjecting the device of claim 1 to an applied voltage.
28. An OLED device comprising a light-emitting layer (LEL) containing a host and an emitting dopant located between a cathode and an anode wherein the dopant is an orange-red light emitting rubrene derivative represented by formula (I):
wherein:
a) there are identical aromatic groups at the 2- and 8-positions;
b) the phenyl rings in the 5- and 11-positions contain only para-substituents identical to the aromatic groups in paragraph a); and
c) the phenyl rings in the 6- and 12-positions are substituted or not in which formula (I) is represented by formula (II):
wherein
R 1 is an aromatic carbocyclic or heterocyclic group;
R 2 is a substituent group;
n is 0–5;
provided that all R 1 are the same; and
provided further, that the R 2 , their location and n value on one ring are the same as those on the second ring;
and wherein the substituent groups are selected so that the rubrene derivative has a wavelength of maximum emission (λ max ) in ethyl acetate solution such that
560 nm<λ max ≦650 nm.
29. An OLED device of claim 28 wherein the substituent groups are selected so that the rubrene derivative has a wavelength of maximum emission (λ max ) in ethyl acetate solution such that
565 nm<λ max ≦625 nm.