Surface Plasmon Enhancement of Eu3+ Emission Intensity in LaPO4/Ag Nanoparticles

Abstract

<jats:p>A promising way to improve the performance of luminescent materials is to combine them with noble metal nanoparticles. Herein, a set of silver/europium-doped lanthanum orthophosphate (Ag/La0.95Eu0.05PO4) nanostructures with different concentrations of silver nanoparticles were prepared and investigated. The presented overlap between the strongest europium (Eu3+) excitation line and the broad silver nanoparticle surface plasmon resonance makes the combination prospective for coupling. X-ray powder diffraction confirmed the monoclinic monazite structure. The transmission electron microscopy revealed particles with a rod-like shape and ~4 aspect ratio. Photoluminescence spectra show characteristic Eu3+ ion red emission. One of the requirements for an enhanced luminescence effect is the precise control of the distance between the noble metal nanoparticles and the emitter ion. The distance is indirectly varied throughout the change of Ag nanoparticle concentration in the La0.95Eu0.05PO4 host. The emission intensity increases with the increase in Ag nanoparticles up to 0.6 mol %, after which the luminescence decreases due to the nanoparticles’ close packing and aggregation leading to the displacement of La0.95Eu0.05PO4 from the vicinity of the metal particles and reabsorption of the emitted light. The emission intensity of La0.95Eu0.05PO4 increases more than three times when the Eu3+ excitation is supported by the localized surface plasmon resonance in the Ag/La0.95Eu0.05PO4 nanostructures.</jats:p>

Optical properties of antimony-borate glass rods co-doped with Eu3+/Ag+ ions

“…The technology of nanocomposite glasses containing noble metal nanoparticles is widely researched due to the possibility of overcoming typical limitations of fused quartz (for instance, bandwidth, luminescence efficiency, and nonlinearity) and high application potential. Optical fibers based on this technology combine both the mechanical and chemical properties of a glass matrix with extended spectroscopic properties of embed metal nanoparticles (NPs) [1][2][3][4]. Therefore, in the technological process of glass synthesis, in addition to active doping (rare earth elements), noble metal ions are introduced into the structure, and then, as a result of controlled thermal treatment, metallic NPs are formed.…”