Electrical and thermoelectric properties of single-wall carbon nanotube doped Bi2Te3

Abstract

The effects of single-wall carbon nanotube (SWCNT) doping in n-type Bi2Te3 bulk samples on the electrical and thermal transport properties have been studied. Bi2Te3 samples doped with 0–5 wt. % SWCNTs were fabricated using solid state reaction and investigated using x-ray diffraction, transmission electron microscopy, and magneto transport measurements. Results show that the 0.5% doping results in the significant enhancement of the Seebeck coefficience to as high as −231.8 μV/K, giant magneto resistance of up to 110%, reduction of thermal conductivity, and change of sign of the Seebeck coefficient from n to p type depending on the doping level and temperature. The figure of merit, ZT, of the optimum SWCNT doped Bi2Te3 was increased by 25%–40% over a wide temperature range compared to the undoped sample.

Towards higher thermoelectric performance of Bi2Te3 via defect engineering

“…Section 3.3). Nonetheless, the Seebeck coefficient may increase due to the electron energy filtering [41][42][43][44] or decrease due to various reasons [43,[45][46][47][48]. The readers are referred to a number of excellent reviews on TE nanocomposites [49][50][51][52][53].…”

On the effect of carbon nanotubes on the thermoelectric properties of n-Bi 2 Te 2.4 Se 0.6 made by mechanical alloying

“…This behavior might appear surprising considering the supposed chemical inertness of the CNTs but comparable doping effects have already been reported. Indeed, n-type doping was observed when n-Bi 2 Te 3 [24,26] or p-Bi 2 Te 3 [25] made by mechanical alloying were mixed with MWCNTs either using ethanol as a dispersant [24,25] or simply by manually mixing them in a mortar [26]. The variations of the Seebeck coefficients (Fig.…”

“…However, while the nano-domains formed using specific synthetic techniques are of the same stoichiometry that the matrix, the addition of foreign nano objects necessitates considering their possible reactivity with the matrix. Hence, it is rather species considered inert that have been considered, such as alumina, silica, fullerenes or carbon nanotube (CNT) [18][19][20][21][22][23][24][25][26].…”

Heterostructured Approaches to Efficient Thermoelectric Materials

“…As demonstrated by Zhang and co--workers, a ~20% relative improvement in zT is obtained for hybrid Bi 2 Te 3 --CNTs over the CNT--free sample. 87 However, the mechanism of this synergistic effect has yet to be resolved. This can be contrasted with the power factor of 160 µW/(m·•K 2 ) that is achieved for the carbon based composite made up of SWNTs, poly(3,4--ethylenedioxythiophene):…”

“…These hybrid structures include structural polymer--CNTs, [69][70][71][72][73][74][75][76][77] conductive polymer--CNTs, 78-81 metal decorated CNTs [82][83][84] and solid--state compound--CNTs. [85][86][87] The main function of CNTs in the polymer is to facilitate the electron transport by creating electron transport pathways and retain the low thermal conductivity as illustrated in Figure 13. Substantial progress in understanding and predictively designing the properties of carbon nanotube (CNT)--based hybrid structures is being made.…”