Multiscale and luminescent, hollow microspheres for gas phase thermometry

Abstract

Recently developed laser-based measurement techniques are used to image the temperatures and velocities in gas flows. They require new phosphor materials with an unprecedented combination of properties. A novel synthesis procedure is described here; it results in hierarchically structured, hollow microspheres of Eu3+-doped Y2O3, with unusual particle sizes and very good characteristics compared to full particles. Solution-based precipitation on polymer microballoons produces very stable and luminescent, ceramic materials of extremely low density. As a result of the – compared to established template-directed syntheses – reduced mass of polymer that is lost upon calcination, micron-sized particles are obtained with mesoporous walls, low defect concentrations, and nanoscale wall thicknesses. They can be produced with larger diameters (~25 µm) compared to known hollow spheres and exhibit an optimized flow behavior. Their temperature sensing properties and excellent fluidic follow-up behavior are shown by determining emission intensity ratios in a specially designed heating chamber. Emission spectroscopy and imaging, electron microscopy and X-ray diffraction results are presented for aerosolizable Y2O3 with an optimized dopant concentration (8%). Challenges in the field of thermofluids can be addressed by combined application of thermometry and particle image velocimetry with such hollow microparticles.

Magnetism and Afterglow United: Synthesis of Novel Double Core–Shell Eu2+‐Doped Bifunctional Nanoparticles

“…Beyond these classical applications, the joining of magnetic and luminescent properties in one single assembly represents a significant step for biotechnological and medical applications such as biosensing, bioimaging, and DNA labeling . Several examples of core–shell magnetic–fluorescent nanoparticles (NPs) have been reported previously in the literature . In general, these particles are composed of a magnetic core combined with a coating layer of luminescent material.…”

<i>Shaping the future with Rare Earth Elements</i> – Model Experiments for “damage monitoring” with [Eu(DBM)<SUB>4</SUB>TEA] and for Recycling of Neodymium(III) Sulfate from Hard Disk Magnets

“…REEs are also highly relevant in technical chemistry as catalysts and as constituents in ceramics. Luminescent REEs have recently been tested for the monitoring of technological processes [5,6,7,8,9], while further attention is also being paid to bioinorganic processes [10], dissipation [11] and REE recycling [12,13].…”