Organic light emitting diode
Disclosed herein are an organic light emitting diode including: at least two light emitting stacks interposed between an anode and a cathode and including at least one light emitting material layer; and a charge generation layer interposed between the light emitting stacks. The charge generation layer includes an N-type charge generation layer and a P-type charge generation layer, wherein the N-type charge generation layer and the P-type charge generation layer are stacked in such direction for the N-type charge generation layer to face the anode and for the P-type charge generation layer to face the cathode. The N-type charge generation layer includes a compound represented by Formula 1. The P-type charge generation layer includes any one selected from the group consisting of a compound represented by Formula 2, a compound represented by Formula 3, and a combination thereof. The material for N-type charge generation layers and the material for P-type charge generation layers of the disclosure can secure low driving voltage and long lifespan of an organic light emitting diode when used in the organic light emitting diode. Compounds of Formulae 1, 2, and 3 are as defined herein.
1. An organic light emitting diode, comprising:
at least two light emitting stacks interposed between an anode and a cathode and comprising at least one light emitting material layer; and
a charge generation layer interposed between the light emitting stacks,
wherein the charge generation layer comprises an N-type charge generation layer and a P-type charge generation layer, the N-type charge generation layer is positioned between the anode and the P-type charge generation layer, and the P-type charge generation layer is positioned proximate to the cathode and the N-type charge generation layer,
wherein the N-type charge generation layer comprises a compound represented by one of the following formulae wherein Ph is a phenyl group:
and
wherein the P-type charge generation layer comprises a compound represented by the following Formula 3:
wherein R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 are each independently hydrogen, a substituted or unsubstituted C 6 to C 12 aryl group, a substituted or unsubstituted C 2 to C 12 heteroaryl group, a substituted or unsubstituted C 1 to C 12 alkyl group, a substituted or unsubstituted C 1 to C 12 alkoxy group, a substituted or unsubstituted C 1 to C 12 ether group, a cyano group, a fluorine group, a trifluoromethyl group, a trifluoromethoxy group, or a trimethylsilyl group, and at least one of R 1 , R 2 , R 3 , R 4 , R 5 , and R 6 comprises a cyano group;
Z 1 and Z 2 are each independently represented by Formula 4:
wherein A and B are each independently hydrogen, a substituted or unsubstituted C 6 to C 12 aryl group, a C 3 to C 12 heteroaryl group, a C 1 to C 12 alkyl group, a C 1 to C 12 alkoxy group, a C 1 to C 12 ether group, a cyano group, a fluorine group, a trifluoromethyl group, a trifluoromethoxy group, or a trimethylsilyl group.
2. The organic light emitting diode according to claim 1 , wherein, in Formulae 3, or 4, a substituent of each of the aryl group, the heteroaryl group, the alkyl group, the alkoxy group, and the ether group is selected from the group consisting of a C 1 to C 12 alkyl group, a C 6 to C 15 aryl group, a C 3 to C 15 heteroaryl group, a cyano group, a fluorine group, a trifluoromethyl group, a trifluoromethoxy group, a trimethylsilyl group, and combinations thereof.
3. The organic light emitting diode according to claim 1 , wherein the compound represented by Formula 3 is a compound represented by the following formulae:
4. The organic light emitting diode according to claim 1 , wherein the N-type charge generation layer is doped with 0.1 wt % to 5 wt % of a first material selected from the group consisting of an alkali metal, an alkali earth metal, and combinations thereof, and the P-type charge generation layer comprises 0.1 wt % to 40 wt % of a second material selected from the group consisting of the compound represented by Formula 3.
5. The organic light emitting diode according to claim 1 , wherein the N-type charge generation layer has a thickness of 0.01% to 10% the overall thickness of the organic light emitting diode, and the P-type charge generation layer has a thickness of 0.005% to 10% the overall thickness of the organic light emitting diode.
6. The organic light emitting diode according to claim 1 , wherein the P-type charge generation layer is formed of the compound represented by Formula 3 alone.
7. The organic light emitting diode according to claim 1 , wherein a difference in LUMO energy level between the N-type charge generation layer and the P-type charge generation layer ranges from 2.5 eV to 4.5 eV.