An organic light-emitting diode comprising:na first electrode;a second electrode facing the first electrode;an emission layer between the first electrode and the second electrode;a first mixed layer between the emission layer and the first electrode and comprising a first compound and a second compound;a second mixed layer between the emission layer and the first mixed layer and comprising a third compound and a fourth compound;a first charge generation layer between the first mixed layer and the first electrode and comprising the first compound, the second compound, and a first charge generation material;a second charge generation layer between the first mixed layer and the second mixed layer and comprising the third compound, the fourth compound, and a second charge generation material; anda buffer layer between the emission layer and the second mixed layer,wherein the first compound and the third compound are each independently a compound represented by Formula 1 below, and the second compound and the fourth compound are each independently a compound represented by Formula 2 below:
›2.↳ 1The organic light-emitting diode of claim 1, wherein a highest occupied molecular orbital (HOMO) energy level of the second compound is 0.1 eV to 0.2 …d2
The organic light-emitting diode of claim 1, wherein a highest occupied molecular orbital (HOMO) energy level of the second compound is 0.1 eV to 0.2 eV lower than a HOMO energy level of the first compound, and a lowest unoccupied molecular orbital (LUMO) energy level of the second compound is 0.1 eV to 0.2 eV lower than a LUMO energy level of the first compound.
›3.↳ 1The organic light-emitting diode of claim 1, wherein a hole mobility of the first compound is higher than a hole mobility of the second compound.d2
The organic light-emitting diode of claim 1, wherein a hole mobility of the first compound is higher than a hole mobility of the second compound.
›4.↳ 1The organic light-emitting diode of claim 1, wherein the first compound and the third compound are each independently a compound represented by Formul…d2
The organic light-emitting diode of claim 1, wherein the first compound and the third compound are each independently a compound represented by Formula 1A:
›5.↳ 1The organic light-emitting diode of claim 1, wherein the first compound and the third compound are each independently Compound 301 below:d2
The organic light-emitting diode of claim 1, wherein the first compound and the third compound are each independently Compound 301 below:
›6.↳ 1The organic light-emitting diode of claim 1, wherein the second compound and the fourth compound are each independently at least one of compounds repr…d2
The organic light-emitting diode of claim 1, wherein the second compound and the fourth compound are each independently at least one of compounds represented by Formulae 2A to 2K below:
›7.↳ 1The organic light-emitting diode of claim 1, wherein the second compound and the fourth compound are each independently at least one selected from Com…d2
The organic light-emitting diode of claim 1, wherein the second compound and the fourth compound are each independently at least one selected from Compounds 2, 8, 14, 15, 16, 20, 31, and 35 below:
›8.↳ 1The organic light-emitting diode of claim 1, wherein the first charge generation material and the second charge generation material are each independe…d2
The organic light-emitting diode of claim 1, wherein the first charge generation material and the second charge generation material are each independently at least one selected from Compound 501 and 502 below:
›9.↳ 1The organic light-emitting diode of claim 1, wherein a mixed weight ratio of the first compound and the second compound is in a range of 6:4 to 8:2.d2
The organic light-emitting diode of claim 1, wherein a mixed weight ratio of the first compound and the second compound is in a range of 6:4 to 8:2.
›10.↳ 1The organic light-emitting diode of claim 1, wherein a mixed weight ratio of the third compound and the fourth compound is in a range of 6:4 to 8:2.d2
The organic light-emitting diode of claim 1, wherein a mixed weight ratio of the third compound and the fourth compound is in a range of 6:4 to 8:2.
›11.↳ 1The organic light-emitting diode of claim 1, wherein a thickness of each of the first mixed layer and the second mixed layer is in a range of 40 nm to…d2
The organic light-emitting diode of claim 1, wherein a thickness of each of the first mixed layer and the second mixed layer is in a range of 40 nm to 60 nm.
›12.↳ 1The organic light-emitting diode of claim 1, wherein an amount of the first charge generation material is in a range of 1 to 3 parts by weight based o…d2
The organic light-emitting diode of claim 1, wherein an amount of the first charge generation material is in a range of 1 to 3 parts by weight based on 100 parts by weight of the first charge generation layer.
›13.↳ 1The organic light-emitting diode of claim 1, wherein an amount of the second charge generation material is in a range of 1 to 3 parts by weight based …d2
The organic light-emitting diode of claim 1, wherein an amount of the second charge generation material is in a range of 1 to 3 parts by weight based on 100 parts by weight of the second charge generation layer.
›14.↳ 1The organic light-emitting diode of claim 1, wherein a thickness of each of the first charge generation layer and the second charge generation layer i…d2
The organic light-emitting diode of claim 1, wherein a thickness of each of the first charge generation layer and the second charge generation layer is in a range of 10 nm to 20 nm.
›15.↳ 1The organic light-emitting diode of claim 1, wherein the buffer layer comprises the compound represented by Formula 1.d2
The organic light-emitting diode of claim 1, wherein the buffer layer comprises the compound represented by Formula 1.
›16.↳ 1The organic light-emitting diode of claim 1, wherein a thickness of the buffer layer is in a range of 0.1 nm to 30 nm.d2
The organic light-emitting diode of claim 1, wherein a thickness of the buffer layer is in a range of 0.1 nm to 30 nm.
›17.↳ 1The organic light-emitting diode of claim 1, wherein the first mixed layer contacts the first charge generation layer.d2
The organic light-emitting diode of claim 1, wherein the first mixed layer contacts the first charge generation layer.
›18.↳ 1The organic light-emitting diode of claim 1, wherein the second mixed layer contacts the second charge generation layer.d2
The organic light-emitting diode of claim 1, wherein the second mixed layer contacts the second charge generation layer.
›19.↳ 1The organic light-emitting diode of claim 1, wherein the organic light-emitting diode comprises at least one layer selected from a hole blocking layer…d2
The organic light-emitting diode of claim 1, wherein the organic light-emitting diode comprises at least one layer selected from a hole blocking layer, an electron transporting layer, an electron injection layer, and a functional layer having an electron transport function and an electron injection function, the at least one layer being between the emission layer and the second electrode.
›20.↳ 1A flat display device comprising: a transistor comprising a source, a drain, a gate, and an active layer; and the organic light-emitting diode of clai…d2
A flat display device comprising: a transistor comprising a source, a drain, a gate, and an active layer; and the organic light-emitting diode of claim 1,nwherein the first electrode of the organic light-emitting diode is electrically connected to the source or the drain.
