Enabling Oxidation Protection and Carrier-Type Switching for Bismuth Telluride Nanoribbons via <i>in Situ</i> Organic Molecule Coating.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38079217.
- Also identified by DOI 10.1021/acs.nanolett.3c02000 and PMC identifier 10755739.
- Licence recorded as CC BY-NC-ND.
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Abstract
Thermoelectric materials with high electrical conductivity and low thermal conductivity (e.g., Bi<sub>2</sub>Te<sub>3</sub>) can efficiently convert waste heat into electricity; however, in spite of favorable theoretical predictions, individual Bi<sub>2</sub>Te<sub>3</sub> nanostructures tend to perform less efficiently than bulk Bi<sub>2</sub>Te<sub>3</sub>. We report a greater-than-order-of-magnitude enhancement in the thermoelectric properties of suspended Bi<sub>2</sub>Te<sub>3</sub> nanoribbons, coated <i>in situ</i> to form a Bi<sub>2</sub>Te<sub>3</sub>/F<sub>4</sub>-TCNQ core-shell nanoribbon without oxidizing the core-shell interface. The shell serves as an oxidation barrier but also directly functions as a strong electron acceptor and p-type carrier donor, switching the majority carriers from a dominant n-type carrier concentration (∼10<sup>21</sup> cm<sup>-3</sup>) to a dominant p-type carrier concentration (∼10<sup>20</sup> cm<sup>-3</sup>). Compared to uncoated Bi<sub>2</sub>Te<sub>3</sub> nanoribbons, our Bi<sub>2</sub>Te<sub>3</sub>/F<sub>4</sub>-TCNQ core-shell nanoribbon demonstrates an effective chemical potential dramatically shifted toward the valence band (by 300-640 meV), robustly increased Seebeck coefficient (∼6× at 250 K), and improved thermoelectric performance (10-20× at 250 K).