The role of electro-sprayed silica-coated zinc oxide nanoparticles to hollow silica nanoparticles for optical devices material and their characterization

Studies of the synthesis of composite zinc oxide-silica (ZnO@SiO2) particles remain a great challenge in terms of obtaining a more precise design and suppress the agglomeration of pure ZnO. However, recent methods encounter problems in production, such as time consumption, multistep processes, and agglomeration of the final product. To this end, a one-step process for the production of composite ZnO@SiO2 particles which has good potential as UV-attenuating materials was proposed via the electrospray method for the first time. The results from this study offer, for the first time, new insights into the design of ZnO@SiO2 as a core-shell particles morphology in which ZnO was coated with SiO2 by using the electrospray method with good control of particle agglomeration. A possible core-shell formation mechanism is proposed to offer an in-depth understanding. When tested as ultraviolet (UV) attenuation materials, the obtained core-shell particles exhibited an activation transmission near 30 % in the wavelength range of 280 - 400 nm under UV A and B light. This activation transmission is better than that of the same composite without a core-shell structure. Another particle with different characteristics (e.g., hollow SiO2) was obtained after the removal of ZnO from the core-shell composite structure. The activation transmission of hollow silica reached approximately 80 % under UV-vis light, indicating that hollow SiO2 has potential applications in future transparent devices.