Ultrahigh thermoelectric power factor in flexible hybrid inorganic-organic superlattice.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 29044102.
- Also identified by DOI 10.1038/s41467-017-01149-4 and PMC identifier 5647338.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Hybrid inorganic-organic superlattice with an electron-transmitting but phonon-blocking structure has emerged as a promising flexible thin film thermoelectric material. However, the substantial challenge in optimizing carrier concentration without disrupting the superlattice structure prevents further improvement of the thermoelectric performance. Here we demonstrate a strategy for carrier optimization in a hybrid inorganic-organic superlattice of TiS<sub>2</sub>[tetrabutylammonium] <sub>x</sub> [hexylammonium] <sub>y</sub> , where the organic layers are composed of a random mixture of tetrabutylammonium and hexylammonium molecules. By vacuum heating the hybrid materials at an intermediate temperature, the hexylammonium molecules with a lower boiling point are selectively de-intercalated, which reduces the electron density due to the requirement of electroneutrality. The tetrabutylammonium molecules with a higher boiling point remain to support and stabilize the superlattice structure. The carrier concentration can thus be effectively reduced, resulting in a remarkably high power factor of 904 µW m<sup>-1</sup> K<sup>-2</sup> at 300 K for flexible thermoelectrics, approaching the values achieved in conventional inorganic semiconductors.