Single-layer polymer light-emitting diodes with high work function gold cathode were fabricated using a series of novel conjugated polyelectrolytes and their neutral precursors: aminoalkyl-substituted polyfluorenes with different 4,7-di-2-thienyl-2,1,3-benzothiadiazole contents. At the current density of 38.7mA/cm2, the external efficiency reaches 0.42% with the Commission Internationale de I'Eclairage coordinates x=0.67 and y=0.33 for PFN-DBT10. It has been shown that these polymers also can be used as electron injection layer in double-layer devices with high work function gold cathode, which favors the manufacture of solution processing multilayer devices. Based on single-layer and double-layer device structures, it was found that the improvement of device performance is attributed to the interface effect between gold cathode and polyelectrolytes layer.