Layer formation, morphology and photoluminescent properties of ultrasonic spray of pre-formed YVO:Eu and SiO coated ZnS:Mn nanoparticles.

In this work, we study the coating process and coating quality of photoluminescent particles deposited on a glass surface in terms of particle distribution and associated film continuity. The dispersion process of commercial ZnS:Mn particles and YVO:Eu particles synthesized by microwave reactor in aqueous solutions onto solid surface was performed using an ultrasonic atomizer. Two methods of particle deposition were used, one by moving the substrates while spraying and in the second the substrates were not moved. The measured zeta potential values of 42.9 mV and 45.3 mV, respectively, show that the dispersion of YVO:Eu nanoparticles, in water, is stable at concentrations of 1.2 wt% and 2.4 wt% without the addition of capping agents. It was also found that the dispersion area increases as the flow rate increases from 1 ml/min to 3 ml/min at constant suspension concentration and spraying time. To stabilize the ZnS:Mn particles in solution, either surfactants or a silica capping layer prepared by a sol-gel process were used. The dispersion area encompassing the major amount of dispersed particles was evaluated, The SEM images demonstrate the effectiveness of the ultrasonic atomizer spraying procedure in the disaggregation nanoparticles, as seen by the reduced mean particle size in the sprayed layer compared to the as prepared powder. Finally, this study suggest that the dispersion process of photoluminescent nanoparticles on a substrate holds the potential for optical traceability.