Actinide Photosensitization in Macromolecular and Nanocrystal Hybrids

The small absorption cross sections (ε < 10 M⁻¹ cm⁻¹) characteristic of Laporte-forbidden transitions in the f-elements have limited the practical implementation of lanthanide and actinide nanoparticles in devices for applications ranging from solar capture to sensing. While various strategies designed to circumvent the problems of low f−f oscillator strengths have been investigated, comparatively little work has explored the utility of organic ligands with high absorption coefficients (ε ≈ 10³−10⁵ M⁻¹ cm⁻¹) in sensitizing excited states in f-element macromolecules and nanocrystals. Our approach investigates actinide hybrid architectures, in which sensitization is achieved with aromatic antenna functioning as terminal light absorbers to convert light into luminescence with unusually high external quantum yields. In addition, chiral constructs allow for luminescence circular polarization for sensing applications and forensics determination. Energy transfer mechanisms in these actinide compounds and particles will be discussed, with an emphasis placed on the generality of this material architecture for realizing ligand-pumped, photon conversion and polarization.