Review of nanostructured devices for thermoelectric applications

Abstract

SummaryA big research effort is currently dedicated to the development of thermoelectric devices capable of a direct thermal-to-electrical energy conversion, aiming at efficiencies as high as possible. These devices are very attractive for many applications in the fields of energy recovery and green energy harvesting. In this paper, after a quick summary of the fundamental principles of thermoelectricity, the main characteristics of materials needed for high efficiency thermoelectric conversion will be discussed, and a quick review of the most promising materials currently under development will be given. This review paper will put a particular emphasis on nanostructured silicon, which represents a valid compromise between good thermoelectric properties on one side and material availability, sustainability, technological feasibility on the other side. The most important bottom-up and top-down nanofabrication techniques for large area silicon nanowire arrays, to be used for high efficiency thermoelectric devices, will be presented and discussed.

Optical Diagnostics of Free Charge Carriers in Silicon Nanowire Arrays

“…The electrical resistivity of SiNWs ( ρ ) can be estimated using the expression , where e is the electron charge and μ is the free charge carrier mobility. In our case, the free hole concentration is known from the optical methods, and the free charge carrier mobility in SiNWs with N > 10 18 cm −3 and diameter more than 20 nm can be considered the same as in bulk c‐Si . A minor role of the surface scattering of free charge carriers on μ in SiNWs is explained by their small mean free path with respect to the nanowire diameter due to impurity scattering.…”

“…A minor role of the surface scattering of free charge carriers on μ in SiNWs is explained by their small mean free path with respect to the nanowire diameter due to impurity scattering. Note that, at the same time, the phonon transport along SiNWs is significantly suppressed by the surface scattering of phonons …”

Recent advances in CNT/graphene based thermoelectric polymer nanocomposite: A proficient move towards waste energy harvesting

“…The current researches on TE materials mainly associated with crystalline nano-structured semiconductor material [52][53][54] These semiconductor materials are extremely doped to generate high value of figure of merit. Bi 2 Te 3 -Sb 2 O 3 based alloy is commercially available TE material with a room temperature ZT of around 1 [53,55].…”

Deployment and exploitation of nanotechnology nanomaterials and nanomedicine

“…Thermoelectric energy conversion seems particularly promising. Nano-structured semiconductors with an optimized boundary layer design contribute to increases in efficiency that could pave the way for a broad application in the utilization of waste heat, for example in automobiles, or even of human body heat for portable electronics in textiles [71].…”