Investigating the effect of electrolyte incorporation on the thermoelectric power factor of bismuth and antimony telluride alloys

<ns3:p> Background Thermoelectric (TE) devices are capable of converting thermal energy into electrical power. The key parameters to assess the performance of a TE material are the power factor ( <ns3:italic>PF</ns3:italic> = <ns3:italic> S <ns3:sup>2</ns3:sup> σ </ns3:italic> , <ns3:italic>S</ns3:italic> and <ns3:italic>σ</ns3:italic> being the Seebeck coefficient and the electrical conductivity, respectively) and the thermal conductivity. In recent years, our group has reported significant <ns3:italic>PF</ns3:italic> improvements rising from the combination of a porous TE solid with an electrolyte. These results were achieved when Sb-doped SnO <ns3:sub>2</ns3:sub> was employed as the TE solid. However, due to the modest TE properties of Sb:SnO <ns3:sub>2</ns3:sub> , not very high <ns3:italic>PF</ns3:italic> values were reached. Here, we evaluate if any <ns3:italic>PF</ns3:italic> improvements can be reached when electrolytes combine with porous bismuth and antimony telluride alloys, the best-performing TE materials at room temperature. Methods Both n-type Bi <ns3:sub>2</ns3:sub> Te <ns3:sub>3</ns3:sub> and p-type Sb <ns3:sub>2</ns3:sub> Te <ns3:sub>3</ns3:sub> porous materials were prepared and then combined with different types of electrolytes. Their synthesis was performed by microwave-assisted hydrothermal route, followed by cold compaction of fabricated nanoparticles. Results Unlike the previous successful results with Sb:SnO <ns3:sub>2</ns3:sub> , no significant <ns3:italic>PF</ns3:italic> improvements were reached in any of the electrolytes tested. This was attributed to the larger carrier concentration and particle dimensions of the bismuth and antimony telluride alloys compared with Sb:SnO <ns3:sub>2</ns3:sub> . Conclusions Thus, the strategy cannot be extended to bismuth and antimony telluride alloys, and very likely will not work with materials with large carrier concentration. </ns3:p>