Characterization of Nanomaterials

Yizengaw, D. E., Godie, E. M., & Manayia, A. H. (2025). Inorganic Chemistry Communications, 114071.

The synthesis of ZnO nanoparticles (ZnO NPs) using J. Schemperiana leaf extracts was investigated, focusing on the influence of calcination temperature on their optical properties. UV–Vis absorption spectroscopy, commonly used to assess the optical behavior of nanomaterials, revealed that the absorbance wavelength of ZnO NPs remained constant across calcination temperatures of 450°C, 550°C, and 650°C, with a strong absorption peak observed at 376.5 nm. This peak corresponds to the surface Plasmon resonance (SPR) of ZnO nanoparticles, a characteristic feature of ZnO in the UV range (350-380 nm).

The study demonstrated that the absorbance intensity of the nanoparticles synthesized at 450°C was higher than those obtained at 550°C and 650°C, indicating that lower calcination temperatures result in nanoparticles with a higher surface area and greater electrostatic interaction. As the calcination temperature increased, the crystallinity and compactness of the ZnO nanoparticles also improved, leading to a decrease in absorption intensity due to nanoparticle aggregation.

These findings emphasize the significance of calcination temperature in tailoring the optical properties of ZnO nanoparticles, with potential implications for their use in various applications such as sensors and photonic devices. Further characterization using FT-IR spectroscopy will provide insights into the role of secondary metabolites in stabilizing the synthesized nanoparticles.

Shah, Bhoomi S., Sunil H. Chaki, and M. P. Deshpande. Next Materials 8 (2025): 100549.

A comparative study was conducted on the thermoelectric properties of CuFeS₂ (CFS) nanoparticles in two distinct phases: tetragonal (TG) and hexagonal (HG). The HG phase was synthesized using a microwave-assisted method, while the TG phase was synthesized via a simple wet chemical method. Both phases were thoroughly characterized using techniques such as powder X-ray diffraction (XRD), energy dispersive analysis of X-rays (EDAX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-Vis spectroscopy.

The XRD analysis confirmed the tetragonal (TG) structure of CFS nanoparticles with specific unit cell parameters (a = b = 5.28 Å, c = 10.42 Å) and revealed the presence of secondary phases, CuS and FeS, which were formed during synthesis but did not significantly affect the thermoelectric properties due to their minimal quantity. These impurities, with bandgaps of 2.2 eV and 1.0 eV respectively, did not impact the electrical conductivity or Seebeck coefficient of the CFS nanoparticles.

The study highlighted that the HG phase of CFS nanoparticles demonstrated superior thermoelectric properties compared to the TG phase, offering promising potential for thermoelectric applications. This research provides a foundational understanding for the development of high-efficiency thermoelectric materials based on CuFeS2 nanoparticles, advancing their application in energy harvesting and related fields.

Gunupuru, R., & Paul, P. (2025). Journal of the Indian Chemical Society, 102(3), 101566.

The synthesis and characterization of 2-amino-5-mercapto-1,3,4-thiadiazole (AMT) functionalized gold nanoparticles (AMTAuNPs) were investigated for their potential in sensing applications. The functionalization process involved anchoring AMT onto citrate-stabilized gold nanoparticles through the thiol group of AMT, forming a stable composite. The synthesis was carried out by adding AMT solution to the gold nanoparticle suspension in a 50:1 ratio, followed by stirring and centrifugation. The functionalized nanoparticles were dispersed in HEPES buffer at pH 7.65.

Characterization of AMTAuNPs was performed using UV-Vis, FT-IR, TEM, and DLS techniques. The FT-IR spectrum confirmed the attachment of AMT to the AuNP surface by showing characteristic peaks corresponding to the amino and thiol groups of AMT. UV-Vis spectroscopy revealed a slight redshift in the absorption peak of AMTAuNPs compared to unfunctionalized AuNPs, indicating successful functionalization. TEM imaging showed the nanoparticles were well-dispersed with an average particle size of approximately 13 nm, while DLS measurements showed a hydrodynamic radius of around 20 nm, accounting for the organic coating.

These findings demonstrate the successful functionalization of gold nanoparticles with 2-amino-5-mercapto-1,3,4-thiadiazole, highlighting their potential for use in sensing and other applications requiring stable, functionalized nanomaterials.