Thermal diffusivity study of nanoparticles and nanorods of titanium dioxide (TiO₂) and titanium dioxide coated with cadmium sulfide (TiO₂CdS)

Thermal lens (TL) technique was used to obtain the thermal diffusivity of nanoparticles (nPs) and nanorods (nRs) of TiO₂ and TiO₂CdS, respectively. The nanoparticles with spherical shape have 25 nm diameter and rod-shapes have different nanometric diameters by length measurements, both contained in ethanol. The nPs and nRs have been successfully prepared by sol-gel and electrospinning techniques. TL provides reliable alternative to measure the thermal diffusivities of semitransparent materials and low thermal diffusivities. The results show that for nanoparticles with different concentrations, for a higher concentration there is an increase in the thermal diffusivity. On the other hand, comparing different nanostructure forms (nanoparticles and nanorods) for the same concentration, a higher value of thermal diffusivity is observed for nanorods. Complementary techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM) and UV-vis spectroscopy were employed to characterize the nanoparticles and nanorods in order to study their morphology, average particle size and absorption spectra. This investigation has future applications for solar cells and electrochemical cells.