This report demonstrates a surface plasmon-enhanced polymer-based LED (PLED) architecture incorporating colloidal Ag nanoparticles in an all-solution fabrication process using orthogonal solvents. Oleylamine capping groups on the Ag nanoparticles provide an individual spacer layer for nanoparticles and prevent exciton dissociation and carrier trapping on Ag nanoparticles in this device structure. The large density of localized surface plasmon (SP) modes, strong exciton-SP mode coupling, and reduced cathode quenching achieved by Ag nanoparticles incorporation between the luminescent polymer and the metal cathode lead to a 20-fold luminance enhancement and a 50-fold current efficiency enhancement.