Downshifting luminescence amplification by multi-phase energy harvesting

Abstract

Lanthanide-based luminescent nanoprobe with the second near-infrared (NIR-II) emission under NIR excitation is widely used in deep tissue bioimaging, biological detection, drug delivery, cancer therapy and information storage due to their unique advantages, such as deep penetration depth, tunable lifetime, and emission wavelength. However, due to the small absorption cross-section and low brightness, the practical application of NIR-II luminescent lanthanide nanoprobe remains a formidable challenge. Here, we present an unconventional nanoparticle design that incorporates co-sensitization along with an additional exterior energy harvesting mechanism. This design expands the energy capture pathway, maximizes the NIR photon absorption capability of as-synthesized nanocrystals, and facilitates energy hopping within Yb3+ sublattices, resulting in remarkably amplified downshifting NIR-II emission from Yb3+ at 980 nm under 808 nm excitation. This study introduces a sophisticated heterogeneous nanostructure that can bring about significant improvements in their photophysical properties, offering promising prospects in the field.