Eu()-doped calcium molybdate nano- and microstructures: microfluidic synthesis and morphology tuning solvent dielectric constant and viscosity control

• Published in: CrystEngComm 2024-10, Vol.26 (42), p.652-664
• Main Authors: Ostellari, Pietro, Tajoli, Francesca, Fortunati, Ilaria, Carofiglio, Tommaso, Badocco, Denis, Pastore, Paolo, Gross, Silvia
• Format: Article
• ISSN: 1466-8033
• DOI: 10.1039/d4ce00549j

A novel and green microfluidic approach was employed for the synthesis of undoped and Eu( iii )-doped calcium molybdate at room and low temperatures. The controlled formation of nano- and microstructures was successfully achieved by tuning the nucleation and growth stages of particle formation through a systematic variation of the viscosity and dielectric constant of the reaction medium, i.e. water and ethanol in different weight ratios and at different temperatures. Thanks to the inherent advantages of the microfluidic approach in terms of mass transport, mixing and heat exchange, it was possible to carry out the reaction at low temperature (−4 °C) in an effective manner and to further control the reaction conditions to achieve the formation of small and monodisperse nanoparticles. The synthesised nano- and microstructures, displaying different morphologies depending on reaction conditions, were investigated from a structural (XRD), dimensional and morphological (TEM, SEM), compositional (ICP-MS), and functional (photoluminescence) point of view. The remarkable photoluminescence properties of pure and Eu( iii )-doped calcium molybdate structures proved that they are promising materials to be employed as phosphors. Microfluidic synthesis of Eu( iii )-doped calcium molybdate structures: by changing the reaction conditions (solvent mixtures, temperature and quenching), particles with different sizes, size distributions and tunable optical properties were obtained.