Multicomponent n-(Bi,Sb)2(Te,Se,S)3 solid solutions with different atomic substitutions in the Bi and Te sublattices

The thermoelectric properties of n-Bi2 - x Sb (x) Te3 - y - z Se (y) S (z) solid solutions are studied in the temperature range 300-550 K. It is shown that an increase in the parameter beta determining the figure-of-merit Z of the material is observed in compositions with the optimally related effective mass of the density of states m/m (0), the carrier mobility mu(0), and the lattice thermal conductivity kappa (L) . Within the temperature range 300-350 K, the parameter beta and the figure-of-merit Z are found to increase in solid solutions with substitutions in both bismuth telluride sublattices Bi -> Sb and Te -> Se, S (x = 0.16, y = z = 0.12) for optimum electron concentrations. An increase in the electron concentration and substitutions of atoms only in the tellurium sublattice bring about an increase in the beta parameter and the value of Z at higher temperatures. Within the range 350-450 K, the parameters beta and Z are observed to increase in a solid solution with a low content of substituted atoms in the tellurium sublattice Te -> Se, S for y = z = 0.09 and, at higher temperatures up to 550 K, in compositions with tellurium substituted by selenium only, with increasing content of substituted atoms.