Enhanced thermoelectric performance in p-type polycrystalline SnSe by Cu doping

Polycrystalline Sn1-xCuxSe samples have been prepared using hot pressing to study the Cu doping effect on carrier concentration in SnSe. Different from Ag, Cu doping decreases the carrier concentration of SnSe at room temperature. The carrier concentration of Cu doped samples increases obviously with temperature, becomes larger than the pristine sample above 523K, and approaches the values of Na doped SnSe at 773K. The enhanced carrier concentration leads to better electrical conductivity, resulting in higher power factors at high temperatures. Due to carrier optimization by Cu, a peak ZT of 0.66 is achieved in Sn0.98Cu0.02Se at 813K.