Enhancement of Thermoelectric Performance of n‐Type PbSe by Cr Doping with Optimized Carrier Concentration

Ti, V, Cr, Nb, and Mo are found to be effective at increasing the Seebeck coefficient and power factor of n‐type PbSe at temperatures below 600 K. It is found that the higher Seebeck coefficients and power factors are due to higher Hall mobility ≈1000 cm 2 V −1 s −1 at lower carrier concentration. A larger average ZT value (relevant for applications) can be obtained by an optimization of carrier concentration to ≈10 18 –10 19 cm −3 . Even though the highest room temperature power factor ≈3.3 × 10 −3 W m −1 K −2 is found in 1 at% Mo‐doped PbSe, the highest ZT is achieved in Cr‐doped PbSe. Combined with the lower thermal conductivity, ZT is improved to ≈0.4 at room temperature and peak ZT s of ≈1.0 are observed at ≈573 K for Pb 0.9925 Cr 0.0075 Se and ≈673 K for Pb 0.995 Cr 0.005 Se. The calculated device efficiency of Pb 0.995 Cr 0.005 Se is as high as ≈12.5% with cold side 300 K and hot side 873 K, higher than those of all the n‐type PbSe materials reported in the literature.