Spectral properties of resonant-cavity, polyfluorene light-emitting diodes

We report on the fabrication and device properties of light-emitting resona nt cavity conjugated-polymer diodes. The microcavity structures were constr ucted using a dielectric mirror, an indium-tin-oxide anode, a green light-e mitting polyfluorene blend, and a metal (cathode) mirror. The best performa nce was obtained for a composite calcium-aluminum cathode, that combines hi gh reflectivity with a low workfunction. This structure emitted electrolumi nescence with a linewidth of 12 nm and a maximum brightness of 300 cd m(-2) at a bias of 35 V with an efficiency of 0.95 cd A(-1). (C) 2000 American I nstitute of Physics. [S0003-6951(00)01230-4].