Large-scale synthesis of lead telluride (PbTe) nanotube-based nanocomposites with tunable morphology, crystallinity and thermoelectric properties

摘要

Graphical abstractDisplay OmittedHighlights•Noble scale-up synthesis of ultra-long PbTe hollow nanofibers with controlled crystallinity & morphology via three-step sequential process.•Variation of Ag content relying on cationic reaction time to give AgxTey-PbTe nanocomposite with different crystallinity.•Electrospun Ag nanofibers of Dav = 60 (aspect ratio: 10,000) and corresponding pure Ag2Te & PbTe nanotubes of Dav = 100 with 20 nm of wall thickness.•The highest Seebeck coefficient of 433 μV/K (300–K) at 30% of Ag in PbTe and the highest power factor of 0.567 μW/mK2at RT with pure PbTe.•Potential for the scale-up procedure synthesis & application for thermoelectric materials by facile tuning the morphology & crystallinity.AbstractA few millimeter-long lead telluride (PbTe) hollow nanofibers with thermoelectric properties was synthesized for the first time with high through manner via three-step sequential process of electrospinning, electrodeposition and cationic exchange reaction. As-synthesized electrospun Ag nanofibers with ultra-long aspect ratio of 10,000 were Te electrodeposited to obtain silver telluride nanotubes and underwent cationic exchange reaction in Pb(NO3)2solution to obtain polycrystalline PbTe nanotubes with average diameter of 100 nm with 20 nm of wall thickness. Variation of the Ag-to-Pb ratio in the AgxTey-PbTe nanocomposites during the cationic exchange reaction enabled to control the thermoelectric properties of resulting 1D hollow nanofibers. The diameter of Ag nanofiber is the key factor to determine the final dimension of the PbTe nanotubes in the topotactic transformation and the content of Ag ion leads to the enhancement of thermoelectric properties in the AgxTey-PbTe nanocomposites. The synthesized 1D nanocomposite mats showed the highest value of Seebeck coefficient of 433 μV/K (at 300 K) when the remained Ag content was 30%, while the power factor reached highest to 0.567 μW/mK2for the pure PbTe nanotubes. The enhancement of thermoelectric properties and the composite crystallinity are elucidated with relation to Ag contents in the resulting 1D nanocomposites.