Enhanced thermoelectric and mechanical properties in hierarchical tubular porous cuprous selenide

Superionic thermoelectric Cu₂Se bulks are successfully acquired via an identical gas reinforced eutectic transformation (gasar) process based on its melting-congruent nature. The gasar synthesis process introduces tubular pores to Cu₂Se matrix, which have hierarchical size and corrugated surface, and are distributed homogeneously and isotopically. The Cu₂Se bulk with such a unique porous structure shows enhanced thermoelectric figure-of-merit up to ∼2.1 at 873 K owing to the conspicuously reduced thermal conductivity, which can be attributed to the increased phonon scattering. Moreover, the porous Cu₂Se bulk also possesses higher mechanical robustness compared with traditional porous-structured material because of the corrugated surface, which is promising for making thermoelectric modules.