Synergistic Optimization of Thermoelectric Performance in P-Type Bi0.48Sb1.52Te3/Graphene Composite

We report the synergistic optimization of the thermoelectric properties in p-type Bi0.48Sb1.52Te3 by the additional graphene. Highly dense Bi0.48Sb1.52Te3 + graphene (x wt%, x = 0, 0.05, 0.1 and 0.15) composites have been synthesized by zone-melting followed by spark plasma sintering. With the help of scanning electron microscopy, the graphene has been clearly observed at the edge of the grain in the composites. Due to the additional graphene, the composites show an improved power factor of 4.8 x 10(-3) Wm(-1)K(-2) with modified carrier concentration and suppressed lattice thermal conductivity. Consequently, synergistic optimization in electrical and lattice properties by additional graphene leads to a great improvement in the figure of merit ZT (1.25 at 320 K).