Electroluminescence of poly(N-vinylcarbazole) (PVK) and its blends with 3-(-2-methacrylate-ethoxy)carbonyl dimethylocoumarine (MK)

Polymer light-emitting diodes (LEDs) have been fabricated from poly(N-vinyl carbazole) (PVK) or blends of PVK and 3-(2-methacryloylethoxycarbonyl)-7-di ethylcoumarin (MK). Thin polymer layers needed for the construction of diod es can be prepared by casting from a solution using the spin-coating techni que. No subsequent processing or heat treatment is required. Mixtures of PV K and MK, with the molar concentration of the latter equal to 0.5%, 1%, 2%, and 8% respectively, were used. In order to achieve bipolarity in the sing le polymer emitter layer, PVK was thoroughly mixed with MK. This approach e nabled us to improve the efficiencies of the prepared LEDs. It was found th at the blend of 99.5% of PVK and 0.5% of MK exhibited the best quantum effi ciencies.