Fabrication of White Polymer Light Emitting Diode with Single Emitting Layer Using Blends of Polyfluorene Based Polymers

We synthesized one blue emitting polymer (P1) and two green emitting polymers (P2, P3) based on polyfluorene with wide photoluminescence spectra, and fabricated white polymer light emitting diodes (W1, W2) with single emitting layer through a blend method. The weight ratio of P1 and P2 or P3 was adjusted to achieve white light emission and to balance the light color. In this study, we achieved (575 cd/m(2), 0.68 cd/A) with bluish white emission using W1 (P1: P2 = 98.0: 2.0), and (554 cd/m(2), 0.8 cd/A) using W2 (P1: P3 = 98.0: 2.0) with greenish white emission. Luminance of devices, which had the donor concentration above 2.0wt%, decreased on account of high concentration quenching.