Coaxial structured Bi2S3–SnS2-MWCNT hybrid nanocomposite with its improved thermoelectric properties

Abstract

Bismuth(III) sulfide (Bi2S3), tin(IV) sulfide (SnS2), and a multi-walled carbon nanotube (MWCNT) are prepared as a hybrid composites (Bi2S3–SnS2-MWCNT) using a simple hydrothermal method. The as-prepared hybrid composite exhibit n-type thermoelectric (TE) characteristics and an enhanced power factor (PF) value. Bi2S3–SnS2 composites are anchored to the surface of MWCNT and form a coaxial structure. The nanostructure formation through bonding between these different materials is confirmed via scanning transmission electron microscopy (STEM) and X-ray photoelectron spectroscopy (XPS). The TE properties of the Bi2S3–SnS2-MWCNT composite is improved by changing the Bi2S3, SnS2 and MWCNT content. The maximum PF (∼150.8 μ·W/m·K2) was obtained for Bi2S3–SnS2-MWCNT composite with Bi:Sn ratio of 7:3 and 2 wt% of CNT. The highest PF values were ∼34 and ∼58 times higher than the PF of Bi2S3 and SnS2 at room temperature. The synthesized Bi2S3–SnS2-MWCNT hybrid nanocomposite can provide important components for fabrication CNT-based TE composites with high conversion efficiency, further advancing TE device.