Plasmon enhanced near-infrared downconversion luminescence of β-NaYF4:Pr3+ nanoparticles by high-ordered Ag nanopillar arrays with tunable nanogaps

Abstract

Large-area high-ordered Ag nanopillar arrays with tunable nanogaps are fabricated by an electroless deposition method. Then, β-NaYF4:Pr3+ nanoparticles (NPs) are spin coated on the Ag nanopillar arrays. Plasmon enhanced near-infrared (NIR) downconversion (DC) luminescence involving the 876 nm (1D2→3F2) and 1017 nm (1D2→3F4,3), as well as the two-step sequential transitions at 915 nm (3P0→1G4) and 990 nm (1G4→3H4), are achieved by Ag nanopillar arrays under the excitation of 444 nm (3H4→3P2) of Pr3+ ions. The influence of different nanogaps between Ag nanopillar arrays on NIR DC luminescence is investigated, and the results show that the optimal nanogap size is 25 nm with a maximum enhancement factor about 3.98. Furthermore, 3D finite-difference time-domain (FDTD) simulation is performed to analyze the enhancement mechanism of NIR DC luminescence. Our study may have potential application in the field of silicon-based solar cells.