Synthesis and investigation of thermoelectric properties of Cu-doped bismuth sulfide (Bi2S3) nanostructures: an experimental approach

• Published in: Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology 2022-11, Vol.24 (11), Article 223
• Main Authors: Arshad, Nadeem, Abbas, Naseem, Ali, Ahsan
• Format: Article
• Language: English
• Subjects: Bismuth sulfides; Characterization and Evaluation of Materials; Chemistry and Materials Science; Copper; Crystal structure; Crystallites; Crystals; Current carriers; Doping; Electrical conductivity; Electrical resistivity; Electricity; Energy resources; Heat conductivity; Inorganic Chemistry; Lasers; Materials Science; Mathematical analysis; Mechanical engineering; Nanostructure; Nanotechnology; Optical Devices; Optics; Photonics; Physical Chemistry; Power factor; Research Paper; Seebeck effect; Spectroscopy; Synthesis; Thermoelectricity; X-ray diffraction
• ISSN: 1388-0764; 1572-896X
• DOI: 10.1007/s11051-022-05592-3

In this study, we have prepared Bi 2 S 3 nanostructures as it has good thermoelectric characteristics, and to enhance the thermoelectric effects, we doped the pure Bi 2 S 3 nanostructures with two different concentrations of copper (Cu). These nanostructures were synthesized at 450 °C. X-ray diffraction (XRD) confirmed the successful synthesis of all samples with an orthorhombic crystal structure. The average crystallite size of Bi 2 S 3 was 26 nm, and after doping of Cu of two different concentrations, reduced crystallite sizes, i.e., 21 nm and 16 nm, were recorded. UV–visible spectroscopy showed that the band gap of Bi 2 S 3 nanostructures increased after doping it with Cu. The electrical conductivity measured by the LCR meter showed an increasing trend with increasing doping concentration. DC conductivity was increased, and resistivity is observed to be decreased after doping of Cu in Bi 2 S 3 nanostructures. This might be due to the contribution of charge carriers from Cu. Enhanced Seebeck coefficients measured in the temperature range of 303–366 K were recorded after every doping concentration. In the end, the power factor was calculated for all three materials, and a surprising increase in power factor was recorded for Bi 1.85 Cu 0.15 S 3 as compared to Bi 2 S 3 and Bi 1.95 Cu 0.05 S 3 nanostructures. Power factors were recorded as ∼ 0.15 μ W / mK 2 , ∼ 0.58 μ W / mK 2 , and ∼ 1.50 μ W / mK 2 for Bi 2 S 3 , Bi 1.95 Cu 0.05 S 3 , and Bi 1.85 Cu 0.15 S 3 nanostructures, respectively. These all-recorded data prove the suitability of Cu-doped Bi 2 S 3 nanostructures for the conversion of heat into electricity, i.e., for thermoelectric devices.