Organic light-emitting devices(OLEDs)

which consist of organic thin films and exhibit light emission under electric current excitation

are expected to be one of the most promising candidates for flat panel display.After Tang reported the efficient double-layer OLEDs

different types of fluorescent materials have been studied and tremendous progress has been made in the past decade.To further improve EL efficiency

the organic phosphorescent materials

which harvest excitation energy of both singlet and triplet states

have been introduced in OLEDs.By employing the phosphorescent materials

the internal quantum efficiency can theoretically reach 100% and emission color can be tuned by modifying the phenylpyridine ligand.The complexes based on Ir(ppy)

3

skeleton have such a simple molecular structure and excellent luminescent properties that many efforts are still focusing on chemical modification of this type of complexes for better electrophosphorescent performance.We synthesized a new iridium(Ⅲ) complex

iridium(Ⅲ) bis(2

5-di(4-ethylphenyl)pyridinato-N

C2′)acetylacetonate [(deppy)

2

Ir(acac)]

based on

2

5-di(4-ethylphenyl)pyridine ligand.ELdevice was fabricated based on

6

%(mass fraction) of(deppy)

2

Ir(acac) doped in CBP.Amaximum luminance efficiency of 23 cd/A and a peak luminance of 10800 cd/m

2

were achieved

the device showed green emission corresponding to a maximum wavelength of 548 nm.On the other hand our electrophosphorescent devices show excellent current saturation behavior at higher current density.