Realizing widespread resonance effects to enhance thermoelectric performance of SnTe

The resonance effect has been used as a theoretical strategy in enhancing the thermoelectric performance. However, its origin and mechanisms are still ambiguous, which complicates the rapid screening of resonance dopants and thereby hinders the improvement of the thermoelectric performance. In this work, we attempt to disclose the mechanism of resonance effect and propose a straightforward method to screen the resonance dopants suitable for SnTe. Hence, two triggering conditions of achieve the resonance effect are proposed. One is the energy correlation between impurity and host states. The other is the position correlation between impurity state level and Fermi level. Based on the two conditions, a variety of elements (including Y, Ru, In, Sb, La, Gd, Lu, Os, Tl and Bi) are selected as the potential resonance dopants suitable for SnTe. Among these elements, we herein re-study the effect of Bi doping on the thermoelectric performance of SnTe. Consequently, a maximum PF of ∼32.46μWcm−1K−2 and the optimal ZT of ∼1.23 were achieved in Sn0·94Bi0·04Te at 873 K due to a high Seebeck coefficient and low thermal conductivity after Bi doping.