Thermoelectric Properties of Ni-substituted Polycrystalline In4Se3

Thermoelectric(TE) materials can convert directly low-grade heat energy to electricity,and vice versa,which is highly expected to play an important role in the future energy management.The application practice demands efficient TE materials made of non-toxic and inexpensive components.Herein,we report a Ni substituted polycrystalline n-type bulk material InNiSe(x = 0 ~ 0.1).Based on density functional theory calculation,Ni tends to substitute at the In3 site in the InSe,which causes a monotonous unit cell volume reduction.At x = 0.01,Ni substitution results in a sharp decrease in the carrier concentration(n) in comparison with that of pure InSe,and then nincreases with the increase of Ni concentration.Ni substitution leads to a performance enhancement from 0.6 for pure InSeto an optimum ZT value of 0.8 at 450 ℃.