Efficient solution-processed double-layer red OLEDs based on a new europium complex with a carbazole group

A new europium complex EuL3(Phen) was used as guest dopant, and a blend of Polyvinylcarbazole and 2‐(biphenyl‐4‐yl)‐5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole (PVK and PBD) as host matrix. Efficient red organic light‐emitting devices (OLEDs) with double‐layer structures were manufactured via a solution‐processed technique. The guest‐doped levels were 1, 3 and 5 wt% relative to the blend mass, respectively. For the 1 wt% doping‐level device, the luminous efficiency and luminance were up to 2.96 cd/A and 635.78 cd/m2 with emissions from both EuL3(Phen) and from the host; for the 3 wt% doping‐level device, the maximum luminous efficiency and luminance were 1.01 cd/A and 370.91 cd/m2 for the single emission from EuL3(Phen) only. Copyright © 2014 John Wiley & Sons, Ltd.