Optimized sample preparation for reliable SEM and AFM analysis: A case-study of sol-gel synthesized TiO2 quantum dots

Turkish

Titanium dioxide (TiO₂) quantum dots represent a class of nanomaterials whose functional properties are strongly influenced by particle size and dispersion state. Despite advances in synthesis routes, their microscopic evaluation remains problematic because intense surface energy driven agglomeration often obscures primary particle features. In this work, anatase TiO₂ quantum dots were produced using a sol gel reflux condensation approach, and the role of post synthesis processing on SEM and AFM image quality was systematically examined. Structural and compositional verification was carried out using X ray diffraction and energy dispersive X ray spectroscopy, while morphological assessment relied on scanning electron and atomic force microscopy. Diffraction analysis verified the exclusive formation of the anatase phase, whereas compositional measurements demonstrated that thermal treatment at 450 °C is required to eliminate residual organic species and restore stoichiometric TiO₂. To address agglomeration during imaging, multiple sample preparation strategies combining mechanical size reduction and solvent assisted dispersion were evaluated. Water based dispersions resulted in pronounced re aggregation during drying, while nonpolar solvents generated surface artifacts that compromised image interpretation. In contrast, ultrasonic dispersion in ethanol following calcination produced the most uniform particle distribution. This protocol enabled consistent visualization of sub 10 nm crystallites assembled into nanoscale clusters and yielded reliable height measurements by AFM. The findings establish a practical preparation strategy for high resolution microscopic analysis of agglomeration prone oxide nanomaterials.