Synthesis of non-agglomerated nanoparticles by an electrospray assisted chemical vapor deposition (ES-CVD) method

Non-agglomerated spherical silicon, titanium and zirconium oxide nanoparticles were prepared using an electrospray assisted chemical vapor deposition (ES-CVD) process. Metal alkoxides in conjunction with an electrospray method were used to introduce charged precursors into a CVD reactor. The ions are produced during evaporation of the charged droplets, and they probably act as seed nuclei (i.e., ion-induced nucleation) and/or, they are attached to the produced particles. The experimental results were compared with those obtained using a conventional evaporation CVD method. The particles generated using the conventional evaporation method were agglomerated to a considerable extent irregardless of the type of particle. Whereas, at the same conditions, high concentrations of non-agglomerated nanoparticles having diameters in the range of 10–40 nm were obtained using the ES-CVD method. This appears to be due to the charging effects of the generated particles, that is, the electrostatic dispersion of unipolarly charged particles. The size of the non-agglomerated particles in the ES-CVD method was reduced as the results of the decease in the concentration of precursors introduced by electrospray.