Characterization of bismuth telluride nanocomposite film with graphene/nanocellulose nanomaterials

Azmi, Azamila Sharmiela (2024) Characterization of bismuth telluride nanocomposite film with graphene/nanocellulose nanomaterials. Project Report. Universiti Teknikal Malaysia Melaka, Melaka, Malaysia. (Submitted)

Text (Full text) Characterization of bismuth telluride nanocomposite film with graphenenanocellulose nanomaterials.pdf - Submitted Version Download (4MB)

Abstract

Bismuth Telluride (Bi2Te3) stands out as a leading thermoelectric material for energy conversion at room temperature, boasting a figure-of-merit (ZT number) close to 1, low lattice thermal conductivity, and high electronic weighted mobility. This study explores an innovative nanocomposite incorporating Graphene and Cellulose Nanofibrils (CNFs) to enhance thermoelectric performance using the electrochemical deposition process for the fabrication and characterization of a Bismuth Telluride nanocomposite film. Before the electrodeposition, a thorough analysis using cyclic voltammetry is conducted. The electrochemical parameters derived from this analysis guide the subsequent fabrication steps. In this study, a consistent voltage of -60mV is used to synthesize pure Bi2Te3 and -90mV for Graphene-CNFs/ Bi2Te3. The inclusion of CNFs, known for their high aspect ratio and inherent mechanical strength, not only enhances the structural integrity of the film but also adds an eco-friendly and sustainable aspect to the process. To prevent cracking due to excess polymer, the CNFs’ surface is coated with a cationic polymer, PDDA, adjusting the concentration up to 1.96% v/v. This modification process suspends the CNFs and disperses them well in the electrolyte. Graphene, renowned for its superior electrical conductivity, complements the intrinsic thermoelectric properties of Bi2Te3, leading to a synergistic improvement in the overall thermoelectric performance. The integration of graphene and nanocellulose results in a smaller microstructure, thereby increasing the film’s porosity. Up to 19.0 wt.% of graphene and CNFs is successfully incorporated into the nanocomposite film. The average grain size of the Graphene-CNFs/Bi2Te3 thermoelectric films decreases by nearly 70% compared to the pure Bi2Te3 film. This study reveals that the synthesized nanocomposites have a smaller grain size, which could enhance the thermoelectric properties of any thermoelectric materials by altering the electron mobility and phonon scattering and contributes to the advancement of sustainable nanomaterials for potential applications in thermoelectric devices and beyond.

Actions (login required)

View Item