A facile solvothermal route has been developed for the preparation of tetragonal europium‐doped yttrium orthovanadate nanoparticles (Eu:YVO4) and is based on a homogeneous precipitation reaction at 120 °C from solutions of rare earth precursors (yttrium acetylacetonate and europium nitrate) and sodium orthovanadate in ethylene glycol or ethylene glycol/water mixtures. The nature of the solvent has a dramatic effect on the morphology and crystallinity of the resulting nanoparticles. Polycrystalline nanoellipsoids (130 × 60 nm) were obtained in pure ethylene glycol, whereas quasispherical nanoparticles (100 nm) with monocrystalline character precipitated in ethylene glycol/water (7:3 by volume) mixtures. To explain these different morphological and structural features, the mechanism of particles formation was investigated. The effects of the doping level on the luminescence properties (emission spectra and luminescence lifetime) were also evaluated to find the optimum nanophosphors. Finally, it is shown that the luminescent efficiency of the quasispherical nanoparticles was higher than that of the nanoellipsoids; this can be related to differences in crystallinity and in impurity content.

The performance of chloride-selective electrodes based on "two-wall" aryl-extended calix[4]pyrroles and multiwall carbon nanotubes is presented. The calix[4]pyrrole receptors bear two phenyl groups at opposite meso-positions. When the meso-phenyl groups are decorated with strong electron-withdrawing substituents, attractive anion-π interactions may exist between the receptor's aromatic walls and the sandwiched anion. These anion-π interactions are shown to significantly affect the selectivity of the electrodes. Calix[4]pyrrole, bearing a p-nitro withdrawing group on each of the meso-phenyl rings, afforded sensors that display anti-Hofmeister behavior against the lipophilic salicylate and nitrate anions. Based on the experimental data, a series of principles that help in predicting the suitability of synthetic receptors for use as anion-specific ionophores is discussed. Finally, the sensors deliver excellent results in the direct detection of chloride in bodily fluids.

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A protocol for the covalent biofunctionalization of silicon-based biosensors using a UV light-induced thiol–ene coupling (TEC) reaction has been developed. This biofunctionalization approach has been used to immobilize half antibodies (hIgG), which have been obtained by means of a tris(2-carboxyethyl)phosphine (TCEP) reduction at the hinge region, to the surface of a vinyl-activated silicon-on-insulator (SOI) nanophotonic sensing chip. The response of the sensing structures within the nanophotonic chip was monitored in real time during the biofunctionalization process, which has allowed us to confirm that the bioconjugation of the thiol-terminated bioreceptors onto the vinyl-activated sensing surface is only initiated upon UV light photocatalysis.