Colloidal assembly of primary vanadate grains for the microstructural control of REVO4 particles

• Grant number: 22/07003-4
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: September 01, 2022
• End date: November 29, 2022
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Paulo Cesar de Sousa Filho
• Grantee: Alexia Lanza Nunes
• Supervisor: Thierry Gacoin
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: École Polytechnique, France
• Associated to the scholarship: 21/11013-2 - Luminescent supraparticles as potential multifunctional sensors, BP.IC

Abstract

The advance in the properties of luminescent inorganic nanoparticles towards innovative applications requires more than the accurate control of size and shape homogeneity via the synthetic routes. Obtaining particles with intense and responsive luminescence for sensing and combining multiple functionalities in a single particle demand a precise tuning of poly- vs. monocristallinity, defect density, porosity, and compositional homogeneity. Rare earth vanadates (REVO4) are very interesting materials for luminescent sensing, especially for nanothermometry, and for studying new synthetic strategies. While the combination orthogonal emissions into submicrometric vanadate supraparticles is one of our current interests, it is also known that the formation of REVO4 nanoparticles by aqueous coprecipitation involves the aggregation of kinetically stable intermediates to generate the final polycrystalline particles. We therefore propose to merge these concepts to achieve a rational design of final size and microstructure of REVO4 structures by the controlled assembly of previously prepared primary grains with known size and composition. Primary 5-10 nm vanadate grains can be synthesized by an aqueous citrate-mediated route. We intend to investigate the effects of pH, ion strength, and antisolvent to modulate the flocculation of primary grains of different compositions into nano- or supraparticles. The structures with selected promising properties will be thermally or hydrothermally treated to further investigate their morphology and microstructure, as well as the orthogonality of downshift and upconversion emissions aiming future applications combining nanothermometry and photodynamic therapy. (AU)