Influence of ytterbium concentration on the emissive properties of Yb:YAG and Yb:Y2O3

The Paul Scherrer Institut has initiated a project to develop a thermophotovoltaic (TPV) converter for residential heating applications. By economic reasons we have decided to design a thermophotovoltaic generator based on Si-cells and, accordingly, to make use of the selective emission properties of ytterbium containing emitter materials. In this contribution, we focus on the emitter materials and present results of an experimental study on the influence of ytterbium concentration on the emissive properties of ytterbium doped yttrium aluminum garnet (YAG) and yttria. The emitter materials were prepared by decomposition of nitrates and by co-precipitation methods with subsequent calcination at elevated temperatures. The polycrystalline materials are characterized by X-Ray diffraction (XRD), particle size distribution (PSD) measurements and Raman and fluorescence microscopy. The emissive properties of the Yb-doped materials have been measured at about 1400 K. Additionally, current-voltage (I–V) curves of t...