As a first milestone we successfully synthesized zirconia and yttria-stabilized zirconia (YSZ) microparticles with very narrow size distributions. The highly efficient reflectivity of heat radiation by very thin coatings of these microparticles was demonstrated by our partners at the TUHH, recently. Currently, we investigate the thermal stability of the particles at temperatures up to 1500 °C and, along these experiments, we study their thermally induced phase transitions. First results indicate that YSZ microparticles are promising building blocks for the development of highly efficient, direct photonic TBCs. Regarding our work towards photonic absorbers/emitters for TPV cells, we prepared novel metallo-dielectric particles consisting of a dielectric core, a thin intermediate metal shell, and an outer dielectric shell.
The core diameter as well as the thickness of both shells are well-controllable by choosing proper reaction conditions during particle synthesis. Recently, we assembled first photonic films using these particles and started to characterize their unique optical properties.