Ionic-liquid-induced microfluidic reaction for water-soluble Ce(1 - x)Tb(x)F3 nanocrystal synthesis

Luminescent lanthanide nanocrystals (NCs) are proposed to be a promising new class of fluorescent labeling agents due to their attractive optical and chemical features including low toxicity, wide photoluminescence (PL) emission and high resistance to photobleaching. In this paper, an ionic-liquid-induced synthesis of Ce(1 - x)Tb(x)F(3) nanoparticle was investigated via utilizing a capillary microreactor. Ionic liquid-[bmim]BF(4) acts as both a fluoride source and stabilizing solvent during the reaction, which was shown to be a key factor that governs luminescence intensity of the obtained nanoparticles. The luminescent properties can be greatly improved by optimizing the volume percentage of [bmim]BF(4). Furthermore, the reaction temperature exerts an influence on the properties of the prepared samples. Experimental results show that the colloidal solutions of Tb(3+)-doped CeF(3) NCs exhibit the characteristic emission of Ce(3+) 5d-4f and Tb(3 + 5) D(4)-(7)F(J) (J = 6-3) transitions with (5)D(4)-(7)F(5) green emission at 542 nm as the strongest peak. The as-prepared samples are found dispersible in water with the quantum yield (in aqueous solution) as 12%, which indicates a potential application on biolabels, light-emitting diodes (LEDs) and redox luminescent switches.