Bohra, Anil K. and Bhatt, Ranu and Singh, Ajay and Basu, Ranita and Bhattacharya, Shovit and Meshram, K. N. and Ahmad, Sajid and Debnath, A. K. and Chauhan, A. K and Bhatt, Pramod and Shah, Kunjal and Bhotkar, Ketan and Sharma, Saloni and Aswal, D. K. and Muthe, K. P. and Gadkari, S. C. (2017) Tellurium-free thermoelectrics: Improved thermoelectric performance of n-type Bi2Se3 having multiscale hierarchical architecture. Energy Conversion and Management, 145. pp. 415-424. ISSN 0196-8904

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Abstract

We report an improved thermoelectric performance of n-type Bi2Se3 bulk alloys synthesized by vacuum melt method followed by vacuum hot-pressing. In the samples so prepared, the synergetic combination of ultra low thermal conductivity (similar to 0.7 W/m K), high Seebeck coefficient (similar to-168 mu V/K), and low electrical resistivity (similar to 15 mu Omega-m) has been observed to successfully lead to a high figure-of-merit (ZT) of similar to 0.96 at 370 K. A detailed characterization of the samples reveals a presence of multiscale hierarchical defect structures i.e. atomic scale disorder arising from a multitude of factors such as large anharmonicity of Bi-Se bond due to electrostatic repulsion between the lone pair of Bi and charge of Se, nanoscale grains and dislocations trapped between mesoscale grains/grain boundaries accompanied by intrinsic layered structure of Bi2Se3. This compact layered grain structure in its consequence offers a high charge carrier mobility and thereby results into a high power factor, while multiscale hierarchical architecture accounts for the scattering of a wider spectrum of phonons leading to an ultra low thermal conductivity. In view of this promising thermoelectric performance together with the presence of copiously available constituent namely Se, the hot-pressed Bi2Se3 presents a technologically suitable and commercially viable alternative to the conventional Bi2Te3 which is based on expensive and scarcely available Te.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/S Elsevier.
Subjects:	Energy Fuels Mechanics Thermodynamics
Divisions:	UNSPECIFIED
Depositing User:	Users 27 not found.
Date Deposited:	09 May 2019 08:13
Last Modified:	09 May 2019 08:13
URI:	http://npl.csircentral.net/id/eprint/2908

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