Organic light emitting diode comprising an organic semiconductor layer
The present invention relates to organic light-emitting diodes that include an anode electrode, a transparent cathode electrode, at least one emission layer and at least one organic semiconductor layer, wherein the at least one emission layer and the at least one organic semiconductor layer is arranged between the anode electrode and the transparent cathode electrode and the organic semiconductor layer includes a first zero-valent metal dopant and a first matrix compound wherein the first matrix comprising at least two phenanthrolinyl groups as well as to a method for manufacturing the same.
1. Organic light emitting diode comprising an anode electrode, a transparent cathode electrode, at least one emission layer and at least one organic semiconductor layer, wherein the at least one emission layer and the at least one organic semiconductor layer is arranged between the anode electrode and the transparent cathode electrode and the organic semiconductor layer comprises a first zero-valent metal dopant and a first matrix compound wherein the first matrix compound comprises at least two phenanthrolinyl groups;
wherein the first zero-valent metal dopant is selected from the group consisting of alkali metal, alkaline earth metal, rare earth metal, Group 3 transition metal and mixtures thereof;
wherein the organic semiconductor layer has a thickness of 100 to 500 nm; and
wherein the organic semiconductor layer is in direct contact with the transparent cathode electrode layer.
2. Organic light emitting diode according to claim 1 , wherein the first matrix compound is a compound of Formula 1
wherein R 1 to R 7 are each independently selected from hydrogen, substituted or unsubstituted C 6 to C 18 aryl group, substituted or unsubstituted pyridyl group, substituted or unsubstituted quinolyl group, substituted or unsubstituted C 1 to C 16 alkyl group, substituted or unsubstituted C 1 to C 16 alkoxy group, hydroxyl group or carboxyl group, and/or wherein adjacent groups of the respective R 1 to R 7 may be bonded to each other to form a ring;
L 1 is a single bond or selected from the group consisting of a C 6 to C 30 arylene group, a C 5 to C 30 heteroarylene group, a C 1 to C 8 alkylene group and a C 1 to C 8 alkoxyalkylene group;
Ar 1 is a substituted or unsubstituted C 6 to C 18 aryl group or a pyridyl group; and
n is an integer from 2 to 4, wherein each of the n phenanthrolinyl groups within the parentheses may be the same or different from each other.
3. Organic light emitting diode according to claim 1 , wherein the transparent cathode electrode comprises a transparent conductive oxide, a metal sulfide, Ag or mixtures thereof.
4. Organic light emitting diode according to claim 1 , wherein the organic light emitting diode comprises a first organic semiconductor layer and a second organic semiconductor layer and the organic light emitting diode further comprises a first emission layer and a second emission layer and the first organic semiconductor layer is arranged between the first emission layer and the second emission layer and the second organic semiconductor layer is arranged between the transparent cathode electrode and the emission layer arranged closest to the transparent cathode electrode.
5. Organic light emitting diode according to claim 1 , wherein the organic light emitting diode further comprises at least one electron transport layer, wherein the one or more electron transport layer is arranged between the one or more emission layer and the one or more organic semiconductor layer.
6. Organic light emitting diode according to claim 5 , wherein the electron transport layer comprises a polar first matrix compound or a non-polar first matrix compound.
7. Organic light emitting diode according to claim 1 , wherein the first zero-valent metal dopant is selected from alkaline earth metal and rare earth metal.
8. Organic light emitting diode according to claim 1 , wherein the first zero-valent metal dopant is comprised in the organic semiconductor layer in an amount of more than 1 wt.-%, based on the total weight of the organic semiconductor layer.
9. Organic light emitting diode according to claim 1 , wherein n is 2 or 3.
10. Organic light emitting diode according to claim 1 , wherein L 1 is a single bond.
11. Organic light emitting diode according to claim 1 , wherein Ar 1 is phenylene.
12. Organic light emitting diode according to claim 1 , wherein R 1 to R 7 are independently selected from the group consisting of hydrogen, C 1 to C 4 alkyl, C 1 to C 4 alkoxy, C 6 to C 12 aryl and C 5 to C 12 heteroaryl.
13. A method for preparing an organic light emitting diode according to claim 1 , wherein the method comprises a step of co-deposition of a first matrix compound comprising at least two phenanthrolinyl groups together with a first zero-valent metal dopant; wherein the first zero-valent metal dopant is selected from the group consisting of alkali metal, alkaline earth metal, rare earth metal, Group 3 transition metal and mixtures thereof.
14. Method according to claim 13 , wherein the process further comprises depositing the transparent cathode electrode using a sputtering process.
15. Organic light emitting diode according to claim 6 , wherein the electron transport layer comprises a non-polar first matrix compound.
16. Organic light emitting diode according to claim 1 , wherein the first zero-valent metal dopant is comprised in the organic semiconductor layer in an amount of more than 3 wt.-%, based on the total weight of the organic semiconductor layer.
17. Organic light emitting diode according to claim 9 , wherein n is 2.
18. Organic light emitting diode according to claim 12 , wherein R 1 to R 7 are independently selected from the group consisting of hydrogen, C 1 to C 4 alkyl and phenyl.