1. Technical Field
The present invention relates to a heterocyclic compound and an organic light-emitting diode including the same, and more particularly, to a heterocyclic compound as an emitting material of an organic light-emitting diode, and a flat panel display device including the organic light-emitting diode.
2. Description of the Related Art
Organic light-emitting diodes (OLEDs) are self-emitting devices that have wide viewing angles, good contrast, quick response times, high brightness, and good driving voltage characteristics. Also, OLEDs can provide multicolored images. Thus, organic light-emitting diodes have drawn attention.
In general, an organic light-emitting diode has a structure including a substrate, and an anode, a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and a cathode (in sequential order) stacked on the substrate. In this regard, the HTL, the EML, and the ETL are mainly formed of organic compounds. When a voltage is applied between the anode and the cathode, holes injected from the anode move to the EML via the HTL, and electrons injected from the cathode move to the EML via the ETL. Carriers, i.e., holes and electrons, recombine in the EML to generate excitons. When the excitons drop from an excited state to a ground state, light is emitted.
The emitting material is the main factor in the light emission efficiency of organic light-emitting diodes. Although fluorescent materials have widely been used as the emitting material, phosphorescent materials are known to theoretically improve light emission efficiency up to 4 times as high as general emitting materials.
4,4′-N,N′-dicarbazole-biphenyl (CBP) is widely known as a phosphorescent host material, and an organic light-emitting diode having high efficiency and good performance may be manufactured using a hole blocking material such as BCP and BAIq or using a BAIq derivative as a host.
In order to reduce the power consumption of an organic light-emitting diode, power efficiency should be improved. Since power efficiency satisfies the equation “power efficiency=(π/voltage)×current efficiency,” voltage should be reduced in order to improve power efficiency. Organic light-emitting diodes manufactured using phosphorescent materials have higher current efficiency than those manufactured using fluorescent materials. However, driving voltage increases when a conventional material, such as BAIq or CBP, is used as a host of the phosphorescent material instead of using a fluorescent material. Accordingly, the power efficiency cannot sufficiently be increased.
In addition, the lifespan of the organic light-emitting diodes manufactured using these host materials is not satisfactory. Thus, there is a need to develop a host material that is stable and has high performance.