Organic light emitting diodes (OLED) employing an Ir complex with coumarin (C6) and acetylacetone (acac) ligands Ir (C6)

2

(acac) are studied.This novel Ir complex can be used both as electron transporting material and light emitting dopant.Comparing the photoluminescence spectra of solid C6 and Ir (C6)

2

-(acac)

the self-quenching effect of molecules was found to be suppressed obviously.To a device structure of ITO (indium tin oxide)/TPD (N

N’-diphenyl-N

N’-bis (3-methyl-phenyl)-1

1’biphenyl-4

4’diamine)/Ir (C6)

2

(acac)/BAlq (bis (2-methyl-8-quinolinolato-N1

O8)-(1

1’-biphenyl-4-olato) aluminum)/Alq

3

(tris-(8-hydroxy-quinoline) aluminum)/Liq (8-hydroxyquinoline lithium)/Al

an orange color (Commission Interationale d’Eclairage (CIE) coordinates

x

=0.43;

y

=0.40) with a max luminance of 3390 cd/m

2

and an efficiency of 1.3 cd/A (quantum efficiency 1.3%) are achieved.Using Ir (C6)

2

(acac) as dopant and Alq

3

as electron transporting host with the same structure

a green color (CIEcoordinates

x

=0.29;

y

=0.58) and a max luminance of 8832 cd/m

2

and an efficiency of 5.6 cd/A (quantum efficiency 1.5%) are obtained.Mechanism of luminescence shows that the orange color luminescence of the device using Ir (C6)

2

(acac) as light-emitting layer origins from the triplet emission of Ir (C6)

2

(acac) dominantly;the green color luminescence of the other device origins from the fluorescence of Alq

3

Ir (C6)

2

(acac)

and a little phosphorescence of Ir (C6)

2

(acac).