Plasmonics in the UV-range constitutes a new challenge due to the increasing demand to detect, identify and destroy biological toxins, enhance biological imaging, and characterize semiconductor devices at the nanometer scale. Silver and aluminum have an efficient plasmonic performance in the near UV region, but oxidation reduces its performance in this range. Recent studies point out rhodium as one of the most promising metals for this purpose: it has a good plasmonic response in the UV and, as gold in the visible, it presents a low tendency to oxidation. Moreover, its easy fabrication through chemical means and its potential for photocatalytic applications, makes this material very attractive for building plasmonic tools in the UV. In this work, we will show an overview of our recent collaborative research with rhodium nanocubes (NC) for Plasmonics in the UV.
Nonstoichiometric ZnO with an excess of Zn atoms (ZnO:Zn) has a long history of use as a green/monochrome
phosphor in electron-excited vacuum fluorescent and field emission displays. The advent of ultraviolet lasers and
light emitting diodes presents the possibility of photoexciting the highly efficient, defect-related green emission
in ZnO:Zn. Here we study experimentally the time-integrated quantum efficiency and the time-resolved photoluminescence
decays of both near band edge and defect emissions in unannealed (ZnO) and annealed (ZnO:Zn)
nanoparticles under femtosecond excitation. A comparison of results using one-photon excitation (excitation
primarily near the particle's surface) versus two-photon excitation (uniform excitation throughout the particle's
volume) elucidates how the quantum efficiencies depend on material properties, such as the spatial distributions
of radiative and nonradiative defects, and on optical effects, such as reabsorption.