Fabrication of dual excitation dual emission phosphor with plasmonic enhancement of fluorescence for simultaneous conversion of solar UV and IR to visible radiation

Abstract

A dual excitation, dual emission phosphor has been fabricated by simultaneous doping of lanthanide ions Er³⁺, Yb³⁺, Eu³⁺ in a highly efficient host YVO₄. YVO₄ doped with Er³⁺, Yb³⁺, Eu³⁺ showed dual excitation i.e., simultaneously excitable by UV and IR radiation and dual emission i.e., bright red fluorescence under UV excitation and intense green under IR excitation. Red DC fluorescence arises due to ⁵D₀–⁷F_J transitions of Eu³⁺. UC emission spectra indicate that Yb³⁺ not only sensitizes Er³⁺ to emit predominantly in the green but also Eu³⁺ to produce a signature red emission. A direct assembly of Ag nanoparticles (NPs) and YVO₄:Er³⁺, Yb³⁺, Eu³⁺ on a suitable substrate showed enhancement of fluorescence of Eu³⁺ red emission under UV excitation. Such studies indicate that a two dimensional conformal transparent layer of a Ag NP–phosphor combined on a silicon solar cell may be used as a DC and UC solar spectrum converter from UV/IR to the visible region where the spectral response of Si is high.