Polymer light-eimtting diodes (PLED) have been demonstrated to possess advantages of sufficient brightness

a broad range of emission color and long operating lifetime. Monocolor PLED has been

so far

made great progress in luminance efficiency and lifetime

specially for green EL emission. However

polymer color emission devices are still under development because of soluble polymer film casting technique which easily make large area rather than small area pixel. So new methods to fabricate polymer color emission devices are being created in device structure. In the work

we developed a new technique to fabricate multicolor polymer EL devices with multiplayer polymer film structure. The device structure consists of ITO/PEDOT/polymers/Ba/Al. The polymers include those which can emit blue

green and red fluorescence

and same color light in a device under electric field. Al electrode acts to protect metal Ba from oxidation

also. The threshold voltages of the device are 2.5V for blue emission

2.5V for green and 1.8V for red

respectively. The CIE coordinates of the EL emissions are

x

=0.16

y

=0.16 for blue

x

=0.34

y

=0.58 for green and

x

=0.60

y

=0.39 for red. EL quantum efficiencies for red

green and blue emission are 1.2%

1.7% and 2.5%

respectively.The multi-layered film structure is promising in potential application of full color polymer light emitting displays.