LaVO4: Eu3+ nano-islands onto silica for achieving fluorescence enhancement and their detection of Fe3+ ions and anti-counterfeiting applications

Rare earth (RE) composite fluorescent materials are favored by researchers in the field of anti-counterfeiting and ion sensing due to their fascinating optical properties. Ultra-small RE fluorescent nanoparticles are anchored on inorganic carriers by a simple preparation method to improve luminous intensity and hydrophilicity, which has not been explored yet. Herein, LaVO4: Eu3+ nano-islands anchored on silica with high fluorescence intensity and easy formation of stable colloidal solution is designed. Through a simple and mild hydrothermal approach, ultra-small LaVO4: Eu3+ nano-islands are highly dispersed on the surface of hierarchical hollow silica sphere (HHSS) to expose more luminescent centers. Remarkably, the stable HHSS@LaVO4: Eu3+ colloidal solution displayed highly sensitive and selective sensor for Fe3+ ions. The "island-sea synergy" structure formed by the LaVO4: Eu3+ nano-islands and the surrounding silica surface makes HHSS@LaVO4: Eu3+ to be an outstanding sensor for the effective detection of iron ions in water. In addition, HHSS@LaVO4: Eu3+ phosphor exhibit unique properties for anti-counterfeiting and encryption applications. These findings provide a promising strategy for the carrierisation of RE luminescent materials to improve optical properties and enable broader applications.