LAUSR

Abstract Employing lanthanide doped upconversion nanoparticles (UCNPs) as near-infrared absorbing photoactive materials is a feasible conception for constructing high efficient and stable narrowband wavelength-selective photodetectors, but limited by its upconversion luminescence efficiency. Herein, we experimentally and theoretically demonstrate upconversion luminescence (UCL) enhancement in monolayer UCNPs using plasmon semiconductor NPs (CsxWO3) and further explore its narrowband near-infrared photodetection application. The UCL improvement of 144 folds in CsxWO3/NaYF4/NaYF4:Yb3+, Er3+ hybrid was realized with the optimized spacer thickness (15 nm) and monolayer UCL. More than three orders enhancement was obtained via the semiconductor plasmon combined with core-shell UCNPs in both CsxWO3/NaYF4/monolayer-NaYF4:Yb3+, Er3+@NaYF4:Yb3+, Tm3+ and CsxWO3/NaYF4 /monolayer-NaYF4:Yb3+, Tm3+@NaYF4:Yb3+, Er3+. Interestingly, the higher enhancement of core's emissions was recorded in core-shell UCNPs by coupling with CsxWO3 NPs. The excitation field amplification dominates the high UCL enhancement, revealed by the UCL dynamics and the calculated electric field intensity. Finally, the high performance narrow photodetectors for 980 nm is constructed employing MAPbI3/CsxWO3/NaYF4/NaYF4:Yb3+, Er3+@NaYF4:Yb3+, Tm3+ hybrids, with narrow line width of 20 nm, high responsivity of 0.33 A/W, detectivity of 4.5 × 1010 Jones, and short response time of 180 ms, which is much better than the previous photodetectors. This finding provides keen approach for developing high efficient/performance UCNPs and narrowband photodetectors.