Abstract
Efficient phosphorescent polymer light-emitting diode with poly(vinylcarbazole) (PVK) doped by two or three iridium complexes in single and bilayer structures are studied. Using spin-rinsed methode for the device, the efficiency for Ir(mppy)3 (Tris-(2-4(4-toltyl) phenylpyridine) device can reach to 48cd/A. With (Ir(mppy)3) as the green emitter and (1-phenylisoquinoline) (acetylacetonate) iridium (III) (Ir(piq)2) as the red emitter the efficiency is as high as 23 cd/A with broad band emission from 500 nm to 720 nm. For white emission a second layer is added with blue emitter ((III) bis [(4,-6-di-fluorophenyl-pyridinato)N,C2] picolinate) (FIrpic) doped in PVK. White light containing three spectral peaks results with efficiency 8.1 cd/A. As the second blue layer is replaced by the fluorescent (Poly (9, 9-dioctylfluorene)) (PFO) white emission with high color rendering index 86 is achieved. The efficiency is 5.7 cd/A with peak luminance 8900 cd/m2. For a given iridium complexes ratio the relative intensity of the green and red emission depends sensitively on the second blue layer.