Manipulating Energy Transfer in Multilayer Lanthanide-Based Nanoparticles for Enhanced NIR-II Luminescence and Lifetime Tuning

Lanthanide-based multilayer nanoparticles exhibiting near-infrared II (NIR-II, 1,000–1,700 nm) emissions have garnered significant interest for diverse frontier optical applications. However, precisely manipulating emissions simultaneously in intensity and lifetime remains challenging. This study proposes a conceptual model of tuning interfacial energy transfer (IET) in a core–shell–shell nanostructure to spatiotemporally control Er³⁺ downconversion luminescence and lifetime. Nanoscale manipulation of the interfacial interactions between Er and Yb sublattices enhances downconversion. Additionally, increasing the thickness of Yb³⁺ interlayer effectively modulates the Nd-Yb-Er energy transfer pathway, simultaneously 8.2-fold of suppressing emission intensity and 1.8-fold prolonging luminescence lifetime. This strategy enables multifunctional tuning of optical properties through combined steady-state excitation and time-gated detection, offering new opportunities for photonic applications such as high-security optical anti-counterfeiting.