Nano-World at Brookhaven: From Core-Electron Dynamics of Tailored (An)isotropic Gold Nanoparticles towards Enhanced Thermal Conductivity in Novel CuC-Ultraconductors

Resolving core-electronic features of cutting-edge materials is a necessity to gain critical insights into their fundamental properties. By utilizing the Hard X-ray Nanoprobe at the NSLS-II at Brookhaven National Laboratory, which provides sub-40 nm spatial resolution, essential electron density changes can be captured at an atomic level. We conducted 2D X-ray absorption near-edge spectroscopy (2D-XANES) at the Au L3-edge (11918.7 eV) on surface-modified (an)isotropic gold nanoparticles, unveiling plasmon-resonance-induced energy shifts in core-electronic transitions. Using the same endstation, we also investigated the enhanced thermal properties of novel CuC ultraconductors, manufactured at Argonne National Laboratory by melt-infusing carbon nanoparticles into polycrystalline copper. Performing 2D-XANES under in-situ heating conditions at the Cu K-edge (8978.9 eV) allows for isolating structural lattice features, which correlate to the material's enhanced thermal conductivity measured to be >10% higher than in standard copper. These results pave the way for efficient nanoparticle tuning with promising applications across the biomedical sector and for next-generation conductors in the power industry, pushing these technologies toward early-stage commercialization.