White polymer light-emitting diodes (WPLEDs) with bilayer structure were fabricated by spin coating method using polymers of different solubilities. The device structure used here is ITO/PEDOT(50nm)/PVK∶PFO-BT∶PFO-DBT(40nm)/PFO(40nm)/Ba(4nm)/Al(120nm)，at the weight ratio of 100∶4∶3 (PVK∶PFO-BT∶PFO-DBT). White fluorescent light emission with CIE coordinates of (0.33, 0.34) is achieved, and the maximal luminance efficiency of 2.4 cd/A and the maximal luminance of 3215 cd/m2 are obtained. By attaching a layer of water-soluble electronic transporting material of PFN to the cathode, the maximal luminance efficiencies increase up to 5.28 cd/A with CIE coordinates kept at (0.34, 0.36), and the device stabitity is also improved.
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