Tellurium‐Free Thermoelectric: The Anisotropic n‐Type Semiconductor Bi₂S₃

Well-oriented crystals of n-type bulk Bi2S3 and Bi2S3-xSex doped with BiCl3 show excellent anisotropic thermoelectric properties. BiCl3 doping in Bi2S3 leads to significant increase in the electrical conductivity, which results to a promising thermoelectric figure of merit, ZT, of ≈0.6 at 760 K.