Multiscale and luminescent, hollow microspheres for gas phase thermometry

Area of Science:

• Materials Science
• Nanotechnology
• Laser-based Measurement Techniques

Background:

• Laser-based techniques for imaging gas flows require advanced phosphor materials.
• Existing materials often lack the necessary combination of properties for high-performance applications.

Purpose of the Study:

• To develop a novel synthesis procedure for hierarchically structured, hollow microspheres of Eu³⁺-doped Y₂O₃.
• To evaluate the material's suitability for laser-based thermometry and particle image velocimetry in gas flows.

Main Methods:

• Solution-based precipitation on polymer microballoons.
• Calcination to form stable, luminescent ceramic microspheres.
• Characterization using emission spectroscopy, electron microscopy, and X-ray diffraction.

Main Results:

• Synthesized hollow microspheres of Y₂O₃ with optimized Eu³⁺ doping (8%).
• Achieved larger diameters (~25 µm) with mesoporous walls and nanoscale wall thicknesses.
• Demonstrated excellent temperature sensing properties and fluidic follow-up behavior.

Conclusions:

• The novel synthesis yields low-density, aerosolizable Y₂O₃ hollow microspheres with superior characteristics.
• These materials are well-suited for advanced laser-based thermometry and velocimetry in thermofluids.
• The developed microspheres offer improved performance compared to existing materials and methods.