Synthetic conditions and their doping effect on β-K2Bi8Se13

In this work the synthetic conditions for K2Bi8Se13 and their effect on its thermoelectric properties were investigated. K2Bi8Se13 was prepared as a single phase using K2Se and Bi2Se3 as starting materials in a furnace or via a reaction using direct flame, followed by remelting or annealing. Seebeck coefficient measurements showed that the doping level in the material is sensitive to the synthetic conditions. Higher synthesis temperatures as well as the flame reaction technique followed by annealing gave more homogenous samples with higher Seebeck coefficient. IR optical spectroscopic measurements showed a wide range of doping level achieved among the different synthetic conditions. These findings suggest that synthetic conditions can act as a useful tool for the optimization of the thermoelectric properties of these materials.