The role of metal film electron density in a surface plasmon polariton assisted light emitter

A novel and simple Sm3+-doped-polymer/Ag/SiO2 trilayer structure was fabricated to investigate the impact of surface plasmon polaritons (SPPs) on the emission quantum efficiency of the dipole emitter Sm3+. Photoluminescence (PL) enhancement factors for samples with different Ag thicknesses (30-70 nm) were found to be different when the thickness of the Sm3+-doped-polymer film was kept constant (220 nm). Theoretical analysis suggests that the electron density of the metal film plays an important role in the SPP assisted PL enhancement process, and this was confirmed in a Sm3+-doped-polymer/Ag/Au/SiO2 multilayer structure.