Microwave-assisted ionic-liquid-based synthesis of highly crystalline CaMoO4:RE3+ (RE = Tb, Sm, Eu) and Y2Mo4O15:Eu3+ nanoparticles

摘要

Fluorescent CaMoO4:RE3+ (RE = Tb, Sm, Eu) nanoparticles, 50-70 nm in diameter, were prepared via a microwave-assisted synthesis in ionic liquids. Herein, the ionic liquid allows heating to high temperatures in the liquid phase (200 degrees C), which guarantees for an optimal crystallization of the nanoparticles. All nanoparticles were indeed readily crystalline without the need of any additional powder sintering. Especially, CaMoO4: Tb and CaMoO4: Eu exhibit high quantum yields of 52% and 82% under UV-excitation (300-320 nm). All compounds were characterized by electron microscopy (SEM), dynamic light scattering (DLS), infrared spectroscopy (FT-IR), energy-dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and fluorescence spectroscopy (FL). In order to shift the excitation to even higher wavelengths, Y2Mo4O15: Eu was firstly realized as a nanomaterial, again, using the microwave-assisted synthesis in ionic liquids. Y2Mo4O15: Eu exhibits a particle size of 2530 nm, and shows a high quantum yield of 67%, too. As this nanomaterial can be excited up to 400 nm, it represents one of the first efficient red-emitting, Eu3+-doped nanomaterials for near-UV excitation (>350 nm) with a simple, low-cost UV-LED. This can be relevant for all kinds of thin-film applications as well as for optical imaging. (C) 2015 Elsevier Masson SAS. All rights reserved.