PANI coupled hierarchical Bi2S3 nanoflowers based hybrid nanocomposite for enhanced thermoelectric performance

Bismuth sulfide (Bi2S3) is a promising material for thermoelectric applications owing to its non-toxicity and high abundance of bismuth (Bi) and sulfur (S) elements on earth. However, its low electrical conductivity drastically reduces the value of the figure of merit (ZT). In this work, we have synthesized three-dimensional (3D) hierarchical Bi2S3 nanoflowers (NFs) by the hydrothermal route and further incorporated them with conducting polymer polyaniline (PANI) by simple chemisorption method. We have investigated the thermoelectric properties of the as-prepared Bi2S3 NFs and PANI/Bi2S3 nanocomposite samples and it is demonstrated that the incorporation of the PANI matrix with the 3D hierarchical Bi2S3 NFs provides a conducting substrate for the easy transport of the electrons and reduces the barrier height at the interface, resulting in similar to 62% increment in the electrical conductivity as compared to Bi2S3 NFs. Moreover, a decrement in the thermal conductivity of the PANI/Bi2S3 nanocomposite is observed as compared to pristine Bi2S3 NFs due to the increased phonon scattering at the interfaces facilitated by the hierarchical morphology of the NFs. Furthermore, an increment in the electrical conductivity and simultaneous decrement in the thermal conductivity results in an overall similar to 20% increment in the figure of merit (ZT) for PANI/Bi2S3 nanocomposite as compared to pristine Bi2S3 NFs. The work highlights an effective strategy of coupling 3D hierarchical metal chalcogenide with conducting polymer for optimizing their thermoelectric properties.

Automated summary

This study demonstrated an effective strategy of coupling 3D hierarchical Bi2S3 nanoflowers with conducting polymer PANI to enhance the electrical conductivity and reduce the thermal conductivity, resulting in an overall improvement in the figure of merit (ZT). This approach provides a promising method for optimizing the thermoelectric properties of materials.