Enhanced thermoelectric performance in ductile Ag2S-based materials via doping iodine

Recently, a deformable and ductile inorganic semiconductor Ag2S has attracted intense attention due to its potential application in self-powered wearable and hetero-shaped electronics. However, the thermoelectric figure of merit (zT) of Ag2S is greatly limited by its extremely low carrier concentration. In this study, via doping I into Ag2S-based materials, we tune the carrier concentration into the optimal range as well as suppressing the lattice thermal conductivity. A maximum zT value of 0.26 is achieved for Ag2S0.7Se0.295I0.005 at 300 K, about three times higher than the matrix compound. More importantly, doping I has little effect on the ductility and deformability of Ag2S-based materials. Our study shows that I-doped Ag2S-based materials are good candidates for developing flexible thermoelectric technologies.