Enhanced thermoelectric efficiency in nanocrystalline bismuth telluride nanotubes

Abstract

We report on the thermal and thermoelectric properties of individual nanocrystalline Bi 2 Te 3 nanotubes synthesized by the solution phase method using 3ω method and a microfabricated testbench. Measurements show that the nanotubes offer improved ZT compared to bulk Bi 2 Te 3 near room temperature due to an enhanced Seebeck coefficient and suppressed thermal conductivity. This improvement in ZT originates from the nanocrystalline nature and low dimensionality of the nanotubes. Domain boundary filtering of low-energy electrons provides an enhanced Seebeck coefficient. The scattering of phonons at the surface of the nanotube leads to suppressed thermal conductivity. These have been theoretically analyzed using the Boltzmann equation based on the relaxation time approximation and Landauer approach. This work clearly demonstrates the possibility of achieving enhancement in thermoelectric efficiency by combining nanocrystalline and low-dimensional systems.

Optimized Active Cooling and Refrigeration using Antidoted Graphene for Heat Management of Microelectronics

“…where k B is the Boltzmann constant, q is the positive or negative elementary charge, f is the probability distribution function of electrons and E f is the Fermi level. The transport rate θ measures the density of free charge carriers passing across a unit area per unit time, and can be determined using an iterative approach [35][36][37][38][39][40] to consider both elastic and inelastic scatterings in diffusive, [41][42][43][44] ballistic [45][46][47][48][49] and quantum hopping transport regimes, [50][51][52][53] as…”

Carbon Nanotubes for Active Refrigeration and Cooling in Micro and Mesoscale Systems

“…where k B is the Boltzmann constant, e is the elementary charge, q of either -e or +e corresponds to the charge of each electron or hole, f is the Fermi-Dirac distribution and E f is the Fermi level. Fortunately, this method of thermopower calculation is valid for the elastic and inelastic diffusive transport, [71][72][73][74] the ballistic transport, [75][76][77][78][79] and the quantum transport. [80][81][82][83] Within each transport regime, the calculation of transport rate (θ) can be different.…”

1-dodecanthiol-assisted aqueous synthesis and characterization of Bi2Te3 nanotubes

“…Several reports indicate significant improvement of the ZT of Bi2Te3 when processed from nanotubes rather than from conventional powders [37,[41][42][43]. Very recently, the work of S. Tadigadapa and al even reports measurements on individual nanotubes displaying 11 to 44% increase of Seebeck coefficient (S) (275 to 357 μV K −1 at T = 300 K), 64 % decrease of the thermal conductivity (κ) and a 88 % increase in ZT (ZT=0.75) compared to bulk Bi2Te3 [44].…”

“…Several examples of Bi2Te3 nanotubes syntheses have already been reported and various approaches are employed to control the morphology of the particles [18][19][20][21][22][23][24][25][26]39] among which can be distinguished the hard-templating synthesis using sacrificial nanotubes, nanorods or nanowires with Bi2Te3 tubes formed from the template surface [38,[44][45][46][47][48][49][50][51][52]. In contrast, the soft-templating approach uses structuring molecular agents [39,53].…”