Size effect on thermoelectric properties of Bi2Te3 nanoparticles

Nanostructured Thermoelectric Films Synthesised by Spark Ablation and Their Oxidation Behaviour

“…All samples showed low thermal conductivity <0.4 W m −1 K −1 , with the lowest value well below 0.2 W m −1 K −1 , comparable to the lowest values reported in the literature, and a nearly tenfold reduction compared to the bulk thermal conductivity [8]. This reduction can be attributed to the nanostructure of the film, introducing grains in the <10 nm range where phonons are scattered at the grain boundaries, as demonstrated before for Bi 2 Te 3 [20,42,44,[47][48][49][50]. The porosity introduces further boundary scattering of the phonons in addition to the grain boundaries [42,48].…”

Phonon Scattering Mechanism for Size‐Dependent Thermoelectric Properties of Bi2Te3 Nanoparticles

“…A marginal increase in resistivity (about 12 %, which is significantly less in comparison to a reduction in thermal conductivity of about 53 %) is observed on a decrease in the size of Bi 2 Te 3 nanoparticles for 150 nm to 30 nm. This is the advantage of this technique of optimization of the size of nanoparticles, that it increases phonon‐phonon scatterings due to an increase in interface volume ratio, which reduces the thermal conductivity κ and enhances the S, but don′t affect the electron‐phonon scatterings much, so as to have minimum effect on ρ or σ, results in significant enhancement of about 142 % in ZT [51] . Resistivity curves of Bi 2 Te 3 nanoparticles of 150 nm to 30 nm are marginally separated and represent metallic conduction (linear temperature dependence) in the wide temperature range with a very small slope [5] .…”

“…This is the advantage of this technique of optimization of the size of nanoparticles, that it increases phonon-phonon scatterings due to an increase in interface volume ratio, which reduces the thermal conductivity k and enhances the S, but don't affect the electron-phonon scatterings much, so as to have minimum effect on 1 or σ, results in significant enhancement of about 142 % in ZT. [51] Resistivity curves of Bi 2 Te 3 nanoparticles of 150 nm to 30 nm are marginally separated and represent metallic conduction (linear temperature dependence) in the wide temperature range with a very small slope. [5] Such behavior of resistivity can be well explained by Bloch-Gruneisen (BG) function of temperature dependence resistivity, (1 = 1 o + AT), detailed method of estimation of electrical resistivity is illustrated elsewhere.…”