Multiscale and luminescent, hollow microspheres for gas phase thermometry

Lothar Bischoff, Michael Stephan, Christina S. Birkel, Christian F. Litterscheid, Andreas Dreizler, Barbara Albert

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


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.

Original languageEnglish (US)
Article number602
JournalScientific reports
Issue number1
StatePublished - Dec 1 2018
Externally publishedYes

ASJC Scopus subject areas

  • General


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