TY - JOUR
T1 - Multiscale and luminescent, hollow microspheres for gas phase thermometry
AU - Bischoff, Lothar
AU - Stephan, Michael
AU - Birkel, Christina S.
AU - Litterscheid, Christian F.
AU - Dreizler, Andreas
AU - Albert, Barbara
N1 - Funding Information:
Financial support of the Deutsche Forschungsgemeinschaft (AL536/14–1, DR374/16–1) and the Darmstadt Graduate School of Excellence Energy Science and Engineering (GSC 1070) is gratefully acknowledged. A.D. is highly grateful for the support by the Gottfried Wilhelm Leibniz program of the Deutsche Forschungsgemeinschaft. We would like to thank Dr. Maren Lepple for help with the DSC measurements, Dipl. Chem. Stephanie Dolique for TEM measurements, and Dominik Götz, M.Sc., for BET measurements.
Publisher Copyright:
© 2018 The Author(s).
PY - 2018/12/1
Y1 - 2018/12/1
N2 - 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.
AB - 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.
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U2 - 10.1038/s41598-017-18942-2
DO - 10.1038/s41598-017-18942-2
M3 - Article
C2 - 29330407
AN - SCOPUS:85043511143
SN - 2045-2322
VL - 8
JO - Scientific reports
JF - Scientific reports
IS - 1
M1 - 602
ER -