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.