Study on the thermoelectric performance of polycrystal SnSe with Se vacancies

Thermoelectric is a green technology to harvest waste heat and convert it to electric energy. N-type SnSe compound with Se vacancies has been synthesized through melting with hot-press. The highest zT value of 0.07 for n-type is obtained at 773 K in sample SnSe0.98 along the parallel pressing direction. In addition, the sample SnSe0.98 has shown a remarkable transition between p-type and n-type semiconductor at around 525 K. Calculation results show that the large band gap could restrict jump of electrons, leading to a low electrical conductivity. More carriers should be induced to increase the carrier density and to enhance the electrical conductivity by substitution elements minus in Se site.