Organic light-emitting device
An organic light-emitting device is provided. The organic light-emitting device comprises a first electrode, a second electrode, and a light-emitting layer interposed between the first electrode and the second electrode. The device further comprises of a phosphorescent dopant and a phosphorescent host that includes at least two hole transport materials. The mixed phosphorescent host materials increase energy transfer efficiency, thereby improving the efficiency and lifespan of the resulting organic light-emitting device.
1. An organic light-emitting device, comprising:
a first electrode;
a second electrode; and
a light-emitting layer interposed between the first electrode and the second electrode,
wherein the light-emitting layer consists of a phosphorescent dopant and two phosphorescent hosts,
wherein the two phosphorescent hosts are
4,4′-biscarbazolylbiphenyl (CBP) and 4,4′-biscarbazolyl-2,2′-dimethylbiphenyl (dmCBP), and
wherein CBP and dmCBP are combined in a weight ratio of about 1:3 to about 3:1.
2. The organic light-emitting device of claim 1 , wherein the light-emitting layer consists of about 70 parts by weight to about 99 parts by weight of the two phosphorescent hosts and about 1 part by weight to about 30 parts by weight of the phosphorescent dopant.
3. The organic light-emitting device of claim 1 , further comprising at least one of a hole injection layer and a hole transport layer interposed between the first electrode and the light-emitting layer.
4. The organic light-emitting device of claim 1 , further comprising at least one of a hole blocking layer, an electron transport layer, and an electron injection layer interposed between the light-emitting layer and the second electrode.
5. An organic light-emitting device, comprising:
a first electrode;
a second electrode; and
a light-emitting layer interposed between the first electrode and the second electrode;
wherein the light-emitting layer consists of:
a phosphorescent dopant;
a first phosphorescent host having a triplet energy of about 2.3 eV to about 3.5 eV; and
a second phosphorescent host having a triplet energy of about 2.3 eV to about 3.5 eV,
wherein the first phosphorescent host and the second phosphorescent host have different highest occupied molecular orbital (HOMO) energy levels and/or different lowest unoccupied molecular orbital (LUMO) energy levels,
wherein the phosphorescent dopant is one material selected from the group consisting of bis(thienylpyridine) acetylacetonate iridium and bis(1-phenylisoquinoline)iridium acetylacetonate,
wherein the first phosphorescent host and the second phosphorescent host are combined in a weight ratio of about 1:3 to about 3:1, and
wherein the first phosphorescent host is 4,4′-biscarbazolylbiphenyl (CBP) and the second phosphorescent host is 4,4′-biscarbazolyl-2,2′-dimethylbiphenyl (dmCBP).
6. The organic light-emitting device of claim 5 , wherein the light-emitting layer consists of about 70 parts by weight to about 99 parts by weight of the phosphorescent hosts and about 1 part by weight to about 30 parts by weight of the phosphorescent dopant.
7. The organic light-emitting device of claim 5 , further comprising at least one of a hole injection layer and a hole transport layer interposed between the first electrode and the light-emitting layer.
8. The organic light-emitting device of claim 5 , further comprising at least one of a hole blocking layer, an electron transport layer, and an electron injection layer interposed between the light-emitting layer and the second electrode.