Doping Effect on Cu₂Se Thermoelectric Performance: A Review

Cu₂Se, owing to its intrinsic excellent thermoelectric (TE) performance emerging from the peculiar nature of "liquid-like" Cu⁺ ions, has been regarded as one of the most promising thermoelectric materials recently. However, the commercial use is still something far from reach unless effective approaches can be applied to further increase the figure of merit (ZT) of Cu₂Se, and doping has shown wide development prospect. Until now, the highest ZT value of 2.62 has been achieved in Al doped samples, which is twice as much as the original pure Cu₂Se. Herein, various doping elements from all main groups and some transitional groups that have been used as dopants in enhancing the TE performance of Cu₂Se are summarized, and the mechanisms of TE performance enhancement are analyzed. In addition, points of great concern for further enhancing the TE performance of doped Cu₂Se are proposed.