Bismuth Sulfide Strongly Coupled to Functionalized MWNTs Hybrids with Improved Thermoelectric Properties
Yu‐Ming Liao, Wenting Liu, Weiping Jia, Bo Wang, Ling Chen, Ke Huang, Matthew J. Montgomery, Jun Qian, Song Lv, Lisa D. Pfefferle
Abstract
Abstract The efficiency of thermoelectric (TE) materials depends on an interplay between various material properties, and strategies for co‐optimizing these properties will be necessary for implementing these materials in the future. In this work, bismuth sulfide (Bi 2 S 3 ) and acid treated multiwalled carbon nanotube (f‐MWNT) composites are fabricated by wet chemical synthesis at room temperature. Bi 2 S 3 is intimately anchored onto the surface of the f‐MWNT to form a coaxial nanostructure. The power factor of the composite is enhanced relative to both the pure Bi 2 S 3 and MWNTs, due to a large enhancement of the electrical conductivity. The enhanced conductivity is attributed to restructuring of the bismuth (Bi) and oxygen (O) bonding environments when Bi 2 S 3 is chemically interfaced with the f‐MWNTs, suggestive of the formation of a strongly coupled complex via BiO/BiS bonds. Strong‐coupling is further supported by scanning transmission electron microscopy, Raman, and diffuse reflectance spectroscopy, which reveal fast charge‐transfer between the Bi 2 S 3 and MWNT when interfaced together. These results support material compositing as a potential strategy for engineering enhanced TE materials.