Thermoelectric nanowires based on bismuth telluride

Orateur : Meriam BEN-KHEDIM (PhD IN)

The continuous miniaturization trends in science andthermoelectricity as an alternative source of energy have promoted intensive research on thermoelectric nanowires. Thermoelectricity efficiency is evaluated by means of the figure of merit ZT=S.T/ρ.λ ; where S, ρ, T and λ are Seebeck coefficient, electrical resistivity, absolute temperature and thermal conductivity, respectively. The one-dimensional structure was chosen in order to improve the figure of merit through quantum and finite size effects. A reduction of the lattice thermal conductivity is expected in such material structure. Fabrication and characterization of auto-organizedbased on bismuth telluride compounds as the most efficient thermoelectric materials at room temperature are reported. Bismuth antimony telluride (Bi0.5Sb1.5Te3) and bismuth telluride selenite (Bi2Te2.3Se0.7) are potentiostatically electrodeposited from perchloric baths using anodic alumina membrane. These templates are prepared via two step anodization process that ensures highly ordered pores. Morphology and composition of the nanowires are investigated using scanning electron microscopy and energy dispersive x-ray spectrometer. X ray diffraction measurements are performed to study crystalline structure. For n-type samples, Seebeck coefficients reachedSeebeck coefficients higher than +160µV/K. Electrical conductivity measurements exhibit lowtests on N-P assembly are in progress to assess the performance of nanowires based thermogenerator.

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