| Summary: | Reducing the thermal conductivity of thermoelectric materials has been a field of intense research to improve the efficiency of thermoelectric devices. One approach is to create a nanostructured thermoelectric material that has a low thermal conductivity due to its high number of grain boundaries or voids, which scatter phonons. Here, we present a new method based on spark ablation nanoparticle generation to create nanostructured thermoelectric materials, demonstrated using Bi<sub>2</sub>Te<sub>3</sub>. The lowest achieved thermal conductivity was <0.1 W m<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula> K<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></semantics></math></inline-formula> at room temperature with a mean nanoparticle size of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>8</mn><mo>±</mo><mn>2</mn></mrow></semantics></math></inline-formula> nm and a porosity of 44%. This is comparable to the best published nanostructured Bi<sub>2</sub>Te<sub>3</sub> films. Oxidation is also shown to be a major issue for nanoporous materials such as the one here, illustrating the importance of immediate, air-tight packaging of such materials after synthesis and deposition.
|
|---|