A series of polycrystalline Sn1-xNaxSe with x = 0.00, 0.02, 0.04, 0.10 were fabricated using hydrothermal synthesis, followed by evacuated-and-encapsulated sintering. Their thermoelectric properties were then evaluated. The thermal constant analyser was used to find the thermal conductivity of each system by using the transient plane source (TPS) technique. ...