Blue polymer light-emitting diodes from poly(9,9-dihexylfluorene-alt-co-2, 5-didecyloxy-para-phenylene)

Deep blue photoluminescence and electroluminescence are demonstrated from a soluble conjugated polymer, poly(9,9-dihexylfluorene-alt-co-2,5-didecyloxy-para-phenylene). The PL quantum efficiency is approximately 40%. Cyclic voltammetry measurements indicate that the highest occupied molecular orbital and lowest unoccupied molecular orbital energies are 5.66 and 2.62 eV below vacuum, respectively. Single-layer and multilayer light-emitting diodes emit deep blue light (peak at ∼420 nm).