Enhancement of thermoelectric power factor in boron and graphene-doped strontium cobalt oxide nanoceramics via sol-gel synthesis

Çınar E., Koçyiğit S., AYTİMUR A., Badali Y., Uslu l.

Materials Science and Engineering: B, cilt.322, 2025 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 322
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1016/j.mseb.2025.118579
  • Dergi Adı: Materials Science and Engineering: B
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, INSPEC, Metadex, Civil Engineering Abstracts
  • Anahtar Kelimeler: Boron, Degradation temperature, Graphene, Nanocomposite, Power factor
  • Bilecik Şeyh Edebali Üniversitesi Adresli: Evet

Özet

In this study, boron and graphene-doped cobalt oxide-based thermoelectric nanoceramic materials were produced and characterized using the sol–gel method. The samples, designated as NC-1, NC-2, and NC-3, were composed of Sr3Co4Oα, Sr2.9B0.1Co4Oα, and 1% graphene-doped Sr2.9B0.1Co4Oα, respectively. The aim of the study was to investigate the effects of boron and graphene doping on the crystal structure, degradation temperature, and thermoelectric properties of the materials. Advanced characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and differential scanning calorimetry-thermogravimetric analysis (DSC-TGA), were employed. Additionally, thermoelectric properties were measured using a physical property measurement system (PPMS). XRD analysis identified orthorhombic (SrCO3) and hexagonal (Sr5Co4O12) structures, with NC-2 exhibiting only Sr5Co4O12 peaks, indicating enhanced phase purity due to boron doping. SEM revealed predominantly spherical structures, with a noticeable reduction in particle diameter for NC-2 and NC-3, attributed to the synergistic effects of boron and graphene. TG analysis showed that boron doping increased the thermal degradation temperature, while graphene further improved thermal stability. NC-3 achieved the highest thermoelectric power factor, demonstrating the synergistic effect of boron and graphene co-doping. Although NC-2 outperformed NC-1, NC-3 exhibited superior performance, indicating that combined doping significantly enhances structural strength and thermoelectric properties.