Multilayer white PLEDs

Multilayer and single layer dye-doped PLEDs.77 In these devices, the polymer layer, typically poly(iV-vinyl carbazole) (PVK see Fig. 1.2) or poly(methyl methacrylate) (PMMA see Fig. 1.3), is only weakly emissive, but is doped with several lower-gap guest dyes, to which the excitation energy is transferred. An appropriate concentration of dyes then yields a white OLED. 

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