Project C1 is dedicated to the theoretical description, modelling and optimization of thermal emission in and from multiscaled materials. The main application area is thermophotovoltaics (TPV), where the emitted thermal energy is converted into electrical energy for power generation. Two approaches are pursued. First, selective far field emitters are developed which are stable at temperatures above 1000°C. In addition, near field systems are investigated which enable to transfer large radiative power by radiation even at temperatures below 1000°C.
In order to tailor efficient TPV-emitters which match specific photovoltaic receivers we realize spectrally selective emitters that show an emission close to that of a black body at short wavelengths, but substantially reduced emission at long wavelengths. We demonstrate such band-edge emitters based on a W-HfO2 refractory metamaterial in cooperation with C7  and a monolayer of monodisperse ZrO2-spheres on a tungsten substrate in cooperation with C4 and C6 . Both structures are stable up to 1000°C.
The study of near field emission concentrates on the thermal radiation in hyperbolic materials  and across nanometer vacuum gaps.
Fig. 1: Absorptivity/Emissivity of the ZrO2-monolayer on tungsten after annealing. Inset: structure (dark blue: W, orange: HfO2, light blue: ZrO2).
|Prof. Dr. rer. nat. Manfred Eich, |
|Dr. rer. nat. Alexander Petrov,|
3. S.-A. Biehs et al.: Blackbody theory for hyperbolic materials. Phys. Rev. Lett. 115, 174301, 2015
... and more on the list of publications.