Manipulating the Injected Energy Flux via Host-Sensitized Nanostructure for Improving Multiphoton Upconversion Luminescence of Tm3+

Combating the concentration quenching effect by increasing the concentration of sensitized rare-earth ions in rational design upconversion nanostructure will make it easier to utilize injection energy flux and transfer it to emitters, resulting in improved upconversion luminescence (UCL). We proposed a host-sensitized nanostructure (active core@luminescent shell@inert shell) to improve multiphoton UCL of Tm3+ based on the LiLnF4 host. Yb3+ ions were isolated in the core as energy absorbents, and Tm3+ was doped in the interior LiYbF4 host shell. Compared with sandwich structured nanocrystals (Y@Y:Yb/ Tm@Y), reverse structure (YbTm@Yb@Y), and fully doped structure (YbTm@ YbTm@Y), the proposed structure achieved the highest efficiency of multiphoton UCL and favored a better FRET-based application performance as the Tm3+ located at an optimized spatial distribution. Furthermore, steady-state and dynamic analysis results demonstrate that by manipulating the spatial distribution of the active ions, excited energy can be tuned to enable multiphoton upconversion enhancement, overcoming the conventional limitations.

Automated summary

Increasing the concentration of sensitized rare-earth ions in a rational design upconversion nanostructure can combat the concentration quenching effect and improve the efficiency of multiphoton upconversion luminescence. The proposed host-sensitized nanostructure achieved the highest efficiency by optimizing the spatial distribution of the active ions, leading to better performance for FRET-based applications.