The role of temperature in the photoluminescence quantum yield (PLQY) of AgS-based nanocrystals.

Highly emissive AgS nanocrystals (NCs) passivated with a gradated shell incorporating Se and Zn were synthesized in air, and the temperature dependence of their photoluminescence quantum yield (PLQY) was quantified in both organic and aqueous media at ∼1200 nm. The relevance of this parameter, measured at physiological temperatures, is highlighted for applications that rely on the near infrared (NIR) photoluminescence of NCs, such as deep NIR imaging or luminescence nanothermometry. Hyperspectral NIR imaging shows that AgS-based NCs with a PLQY in organic media of about 10% are inefficient for imaging at 40 °C through 20 mm thick tissue with low laser irradiation power densities.

Demonstration of tritium adsorption on graphene.

In this work, we report on studies of graphene exposed to tritium gas in a controlled environment. The single layer graphene on a SiO/Si substrate was exposed to 400 mbar of T, for a total time of ∼55 h. The resistivity of the graphene sample was measured during tritium exposure using the van der Pauw method.

Versatile Confocal Raman Imaging Microscope Built from Off-the-Shelf Opto-Mechanical Components.

Confocal Raman microscopic (CRM) imaging has evolved to become a key tool for spatially resolved, compositional analysis and imaging, down to the μm-scale, and nowadays one may choose between numerous commercial instruments. That notwithstanding, situations may arise which exclude the use of a commercial instrument, e.g.

New Constraint on the Local Relic Neutrino Background Overdensity with the First KATRIN Data Runs.

We report on the direct search for cosmic relic neutrinos using data acquired during the first two science campaigns of the KATRIN experiment in 2019. Beta-decay electrons from a high-purity molecular tritium gas source are analyzed by a high-resolution MAC-E filter around the end point at 18.57 keV.

Accurate Reference Gas Mixtures Containing Tritiated Molecules: Their Production and Raman-Based Analysis.

Highly accurate, quantitative analyses of mixtures of hydrogen isotopologues-both the stable species, H, D, and HD, and the radioactive species, T, HT, and DT-are of great importance in fields as diverse as deuterium-tritium fusion, neutrino mass measurements using tritium β-decay, or for photonuclear experiments in which hydrogen-deuterium targets are used. In this publication we describe a production, handling, and analysis facility capable of fabricating well-defined gas samples, which may contain any of the stable and radioactive hydrogen isotopologues, with sub-percent accuracy for the relative species concentrations. The production is based on precise manometric gas mixing of H, D, and T.