The effect of plasmonic near field tuning on spontaneous emission intensity of dual emitting ZnO:Er3+ nanoparticles

• Dual emitting ZnO:Er3+ nanoparticles synthesized by co precipitation method.
• Silver nanoparticles (Ag NP) synthesized by colloid chemistry.
• ZnO:Er3+ NPs optimally conjugated with Ag NPs.
• Plasmonic enhancement of fluorescence by 420% under UV excitation observed.
• FDTD simulation of exact Ag NP near field, correlation with fluorescence enhancement.

The effect of plasmonic near field of silver nanoparticles (Ag NPs) on luminescence of Er3+ doped ZnO nanoparticles that exhibit dual mode excitation has been investigated. The surface plasmon resonance (SPR) energy is shown to play an important role in optical enhancements (under UV excitation) and quenching (under IR excitation) in ZnO:Er3+ NPs optimally conjugated with Ag NPs. Enhancement of total luminescence yield by 420% from ZnO:Er3+ NPs has been realized due to proximity of Ag NPs under UV excitation. The near field generated by exact Ag NP and their extinction properties were simulated through Finite difference time domain method and a direct correlation with observed fluorescence enhancement as well as quenching could be established.