Ultrasonic Spray Pyrolysis For Nanoparticles Synthesis Ultrasonic spray pyrolysis for nanoparticles synthesis. This article presents new findings regarding the effects of precursor drop size and precursor concentration on product particle size and morphology in ultrasonic spray pyrolysis. Large precursor drops (diameter > 30 μm) generated by ultrasonic atomization at 120 kHz yielded particles with holes due to high solvent evaporation rate, as predicted by the conventional one particle [...]