High red, green, and blue color purity electroluminescence from MEH-PPV and polyalkyfluorenes-based bright white polymer light emitting displays

A series of white polymer light emitting displays (PLEDs) based on a polymer blend of polyalkylfluorenes and poly(2-methoxy-5,2'-ethyl-hexyloxy-1,4-phenylene vinylene) (MEH-PPV) was developed. MEH-PPV or red light emitting alkyfluorene copolymer (PFR) was blended with blue light emitting alkyfluorene copolymer (PFB), and MEH-PPV was blended with both green light emitting alkyfluorene copolymer (PFG) and PFB to generate white light emission PLEDs. Low turn on voltage (2.7 V), high brightness (12,149 nits), high efficiency (4.0 cd/A, 4.0 lm/W), and good color purity (Commission Internationale de L'Eclairage (CIEx,y) co-ordinates (0.32, 0.34)) were obtained for the white PLEDs based on the PFB and MEH-PPV polymer blend. Exciplex formation in the interface between PFR and PFB induced a new green emission peak for these two components based white PLEDs. As a result, strong white emission (4078 nits) was obtained by mixing the red, green, and blue (RGB) three primary colors. High color purity of blue (CIE, x = 0.14, y = 0.08), green (CIE, x = 0.32, y = 0.64) and red (CIE, x = 0.67, y = 0.33) emissions was achieved for white PLEDs combining with dielectric interference color-filters. (c) 2006 Wiley Periodicals, Inc.