The effect of dark layer on lanthanide luminescence in inverted nanostructures

The frontier goal of nanomaterial engineering is to achieve atomic-level precision control to fabricate nanostructures with desired properties. However, the detailed understanding of how the spatial arrangement of lanthanide ions within core-shell structures affects their optical properties and energy flux dynamics remains incomplete. In this study, we explored the profound impact of ion positioning on photoluminescence and energy transfer within lanthanide-doped core-shell nanostructures, introducing a novel structural inversion effect (SIE). We observe that the luminescence intensity of lanthanides is significantly enhanced when sensitizers and activators are doped further from the outer layer, whereas closer doping to the outer layer leads to a marked reduction in luminescence. We also have elucidated the critical interplay between the dark layer and nearby emitters. This interaction fosters nonradiative transitions and subsequent energy dissipation. Our findings not only deepen the comprehension of optical behaviors in lanthanide-doped core-shell architectures but also provide innovative theoretical frameworks for enhancing the design and functionality of lanthanide-based nanomaterials, with implications for a range of applications. © 2025 Elsevier B.V.