Rare-Earth Mediated Engineering in ZnSe@ZnS:Eu^{3 +} to Simultaneously Achieve Structural Modulation and Atomic Eu...

Lanthanide ions offer distinctive optical features but have weak absorption due to parity-forbidden 4f-4f transitions, prompting strategies to boost absorption through host matrices, dopant engineering, and optimized nanostructures. Ln-doped colloidal QDs enhance photoluminescence and broaden absorption for applications in solar energy and photo-catalysis, yet integrating Ln³⁺ into hosts and achieving efficient energy transfer, especially in Ln-doped II-VI sulfide QDs, still remains challenging and unsolved. Here, we report a "dual hard-base anchoring" strategy for synthesizing rare-earth doped ZnSe@ZnS:Eu³⁺ QDs. Interestingly, based on the fluoride-oleylamine synthetic interactions, Eu³⁺ forms atomic Eu doping sites on the QD surface, as shown by extended X-ray absorption fine-structure analysis. Optimized temperature, Eu³⁺ doping, and F^- concentration yield controlled morphologies, including tetragonal growth, tip, island, and coupled flower forms. Surface passivation with oleylamine and a 1,10-phenanthroline ligand broadens Eu³⁺-related emission (⁵D₀→⁷F₂/⁷F₁). The approach also applies to six other rare-earth dopants, delivering high performance in X-ray imaging and enabling rare-earth related new applications.