Synergistic optimization of thermoelectric performance in earth-abundant CuZnSnS by inclusion of graphene nanosheets.

Earth-abundant quaternary chalcogenide semiconductors with complex structures, such as copper zinc tin sulphide (CuZnSnS; CZTS), have the potential to become economic and non-toxic thermoelectric materials. However, the inferior power factor of CZTS, due to its insignificant electrical conductivity, negates the advantage of inherent small thermal conductivity. In the present report, the thermoelectric properties of CZTS composites integrated with graphene nanosheets (GNs) CZTS/x (x = 0.

Probing the path for achieving a broad temperature plateau of the figure of merit in thermoelectric nanocomposite materials.

The efficiency of a thermoelectric device depends directly on the average figure of merit (zT) of the material. A high average zT requires a broad temperature plateau with a high zT, but state-of-the-art thermoelectric materials display a peaked zT over a narrow temperature range due to a strong temperature dependence of transport properties. In this work, using Boltzmann transport theory, we systematically investigate the underlying physics and propose a strategy for attaining a broad temperature plateau of zT through proper engineering of the interfacial barrier height in PbTe nanocomposite material.

Tailoring of Seebeck coefficient with surface roughness effects in silicon sub-50-nm films.

The effect of surface roughness on the Seebeck coefficient in the sub-50-nm scale silicon ultra thin films is investigated theoretically using nonequilibrium Green's function formalism. For systematic studies, the surface roughness is modelled by varying thickness periodically with square wave profile characterized by two parameters: amplitude (A 0) and wavelength (λ). Since high Seebeck coefficient is obtained if the temperature difference between the ends of device produces higher currents and higher induced voltages, we investigate how the generated current and induced voltage is affected with increasing A 0 and λ.