Investigation of bismuth doping effect on electrical and thermal properties of n-type PbSnS2

In this work, we have studied the influence of bismuth on thermoelectric properties of ${\mathrm{Pb}}_{(1-x)}{\mathrm{Bi}}_x\mathrm{Sn}{S}_2$ (0 $\le$ x $\le$ 0.1). It was demonstrated that the addition of bismuth significantly increases electrical conductivity from 83.5 ${\mathrm{Sm}}^{-1}$ to 1407 ${\mathrm{Sm}}^{-1}$ at 750 K. The maximum thermoelectric figure of merit $z{T}_{max}=0.55$ was achieved at 750 K. Furthermore, the mechanisms underlying these improvements were described through density functional theory (DFT) calculations. Our results indicate that the increase in electrical conductivity is linked to modifications in the electronic structure. This study highlights the potential of ${\mathrm{Pb}}_{(1-x)}{\mathrm{Bi}}_x\mathrm{Sn}{S}_2$ as an effective thermoelectric material and provides insights into optimizing its properties through strategic doping.