Plasmon enhanced near-infrared quantum cutting and simulation analysis of β-NaYF_4:Tb^3+, Yb^3+ doped with Ag nanoparticles

Nanoscale quantum cutting (QC) phosphor β-NaYF4:Tb3+,Yb3+ nanoparticles (NPs) and noble metal Ag NPs are synthesized respectively, then β-NaYF4:Tb3+,Yb3+ NPs are doped with Ag NPs uniformly. Experimentally, plasmon enhanced near-infrared (NIR) QC involving a Yb3+ ion at 977nm (2F5/2→2F7/2) emission is achieved under 377nm (7F6→5D3) excitation of Tb3+ ions. The QC luminescence intensity first increases, then decreases with the increase of Ag NPs concentration. The maximum QC luminescence enhancement factor reaches 2.4 when the concentration of Ag NPs is 0.25%. Theoretically, a 3D finite-difference time-domain (FDTD) simulation is carried out to numerically estimate the electric field enhancement around Ag NPs, and then the theoretical QC luminescence enhancement factor is calculated. Our study may provide a promising QC layer on the top of silicon-based solar cells to improve the photovoltaic conversion efficiency.