Organic element for electroluminescent devices
View Patent ↗An electroluminescent device including a cathode, an anode, and having therebetween a light-emitting layer including a boron complex represented by Formula (I), wherein: X represents hydrogen or a substituent; V 1 through V 8 represent hydrogen or an independently selected substituent, provided that adjacent substituents cannot join together to form an aromatic ring group and provided at least one of V 2 and V 3 represents a substituent; L 1 and L 2 represent independently selected substituents; and an anthracene compound containing an anthracene nucleus substituted in the 9- and 10-positions with independently selected aryl groups containing from 6 to 24 carbon atoms, and wherein the anthracene nucleus can be further substituted provided the anthracene nucleus does not contain an aromatic substituent in positions 1-8.
1. An electroluminescent device comprising a cathode, an anode, and having therebetween a light-emitting layer comprising:
(a) a boron complex represented by Formula (I),
wherein:
X represents hydrogen or a substituent;
V 1 through V 8 represent hydrogen or an independently selected substituent, provided that adjacent substituents cannot join together to form an aromatic ring group and provided at least one of V 2 and V 3 represents a substituent;
L 1 and L 2 represent independently selected substituents;
wherein X, V 1 through V 8 , L 1 and L 2 are chosen such that the boron complex represented by Formula (I), when dissolved in ethyl acetate at a concentration of less then 10 −3 molar, has a maximum fluorescence emission between a wavelength of 425 nm and 435 nm and a quantum yield of 0.70 to 1.0; and
(b) an anthracene compound containing an anthracene nucleus substituted in the 9- and 10-positions with independently selected aryl groups containing from 6 to 24 carbon atoms, and wherein the anthracene nucleus can be further substituted provided the anthracene nucleus does not contain an aromatic substituent in positions 1-8,
wherein the light-emitting layer emits blue light.
2. The device of claim 1 wherein at least one of V 2 and V 3 represents an aryl group containing from 6 to 24 carbon atoms.
3. The device of claim 1 wherein at least one of V 2 and V 3 represents an aryl group containing from 6 to 24 carbon atoms and at least one of V 6 and V 7 represents an independently selected aryl group containing from 6 to 24 carbon atoms.
4. The device of claim 1 wherein X represents hydrogen, cyano, an alkyl group containing from 1 to 24 carbon atoms, or an aryl group containing from 6 to 24 carbon atoms.
5. The device of claim 1 wherein X represents hydrogen.
6. The device of claim 1 wherein the maximum fluorescence emission is between a wavelength of 430 nm and 435 nm.
7. The device of claim 1 wherein X, V 1 through V 8 , L 1 and L 2 are chosen such that the color of light emitted by the light-emitting layer has a CIE x coordinate value in the range of 0.10 to 0.20 and a CIE y value of 0.10 or less, but greater than 0.
8. The device of claim 1 wherein the boron complex is represented by Formula (II),
wherein:
X represents hydrogen or an alkyl group containing from 1 to 24 carbon atoms;
V 10 through V 15 represent hydrogen or an independently selected substituent, provided that adjacent substituents cannot join together to form an aromatic ring group;
each R can be the same or different and each represents an independently chosen substituent provided adjacent R groups can combine to form a ring group; n and m are independently 0-5; and
L 1 and L 2 represent independently selected substituents.
9. The device of claim 8 wherein X and V 10 through V 15 represent hydrogen, and L 1 and L 2 represent fluoro.
10. The device of claim 8 wherein each R independently represents an alkyl group containing from 1 to 24 carbon atoms or aryl group containing from 6 to 24 carbon atoms, provided adjacent R groups can combine to form a ring group.
11. The device of claim 1 wherein the anthracene is represented by Formula (III)
wherein:
Ar 1 and Ar 2 are independently chosen aryl groups containing from 6 to 24 carbon atoms;
W 1 through W 8 independently represent hydrogen or an alkyl group containing from 1 to 24 carbon atoms.
12. The device of claim 11 wherein Ar 1 and Ar 2 are independently chosen from the group consisting of a phenyl group, a naphthyl group, and a biphenyl group.
13. The device of claim 11 wherein W 1 through W 8 represent hydrogen.
14. The device of claim 1 including an electron-transporting layer between the light-emitting layer and the cathode and contiguous to the light-emitting layer, wherein the electron-transporting layer comprises an anthracene derivative of Formula (IV),
wherein:
R 1 and R 6 each independently represent an aryl group containing from 6 to 24 carbon atoms;
R 2 -R 5 and R 7 -R 10 are each independently chosen from hydrogen, alkyl groups containing from 1 to 24 carbon atoms and aromatic groups containing from 6 to 24 carbon atoms.
15. The device of claim 14 wherein the electron-transporting layer includes an alkali metal or alkali metal compound.
16. The device of claim 14 wherein the electron-transporting layer includes an organic lithium compound represented by Formula (V),
(Li + ) m (Q) n Formula (V)
wherein:
Q is an anionic organic ligand; and
m and n are independently selected integers selected to provide a neutral charge on the complex.
17. The device of claim 1 wherein the boron complex is present in an amount of 0.1 to 10.0 weight percent of the light-emitting layer.
18. An electroluminescent device comprising a cathode, an anode, and having therebetween:
(a) a light-emitting layer comprising:
(i) a boron complex represented by Formula (I),
wherein:
X represents hydrogen or a substituent;
V 1 through V 8 represent hydrogen or an independently selected substituent, provided that adjacent substituents cannot join together to form an aromatic ring group and provided at least one of V 2 and V 3 represents a substituent; and
L 1 and L 2 represent independently selected substituents;
wherein X, V 1 through V 8 , L 1 and L 2 are chosen such that the boron complex represented by Formula (I), when dissolved in ethyl acetate at a concentration of less then 10 −3 molar, has a maximum fluorescence emission between a wavelength of 425 nm and 435 nm and a quantum yield of 0.70 to 1.0; and
(ii) an anthracene compound containing an anthracene nucleus substituted in the 9- and 10-positions with independently selected aryl groups containing from 6 to 24 carbon atoms, and wherein the anthracene nucleus can be further substituted provided the anthracene nucleus does not contain an aromatic substituent in positions 1-8;
wherein the light-emitting layer emits blue light; and
(b) an electron-transporting layer between the light-emitting layer and the cathode and contiguous to the light-emitting layer, wherein the electron-transporting layer comprises:
(i) an anthracene derivative of Formula (IV),
wherein:
R 1 and R 6 each independently represent an aryl group containing from 6 to 24 carbon atoms;
R 2 -R 5 and R 7 -R 10 are each independently chosen from hydrogen, alkyl groups containing from 1 to 24 carbon atoms and aromatic groups containing from 6 to 24 carbon atoms; and
(ii) an alkali metal or an alkali metal compound.
19. The device of claim 18 wherein the alkali metal compound comprises an organic lithium compound represented by Formula (V),
(Li + ) m (Q) n Formula (V)
wherein:
Q is an anionic organic ligand; and
m and n are independently selected integers selected to provide a neutral charge on the complex.