Fluorescence Quenching Effects of Carbon Shells on Eu₂O₃ Nanoparticles

The performance of fluorescent nanoparticles is significantly affected by fluorescence quenching materials, such as impurities. In this study, the fluorescence quenching effects of carbon shells on Eu₂O₃ nanoparticles were investigated by synthesizing bare and carbon-grafted Eu₂O₃ nanoparticles with different amounts of grafted carbon using dextrose as a carbon source to simulate carbon contaminations and investigate this issue and by measuring their photoluminescence (PL) spectra and absolute quantum yields (QYs). The synthesized Eu₂O₃@C core-shell nanoparticles were further grafted with the organic photosensitizer 2,6-pyridinedicarboxylic acid (PDA) to enhance their QYs. It was found that as the grafted carbon amount increased, the PL intensity and QY decreased, demonstrating the fluorescence quenching effect of the grafted carbon layers. Therefore, it is better to avoid carbon contaminations in fluorescent nanoparticles during synthesis in order to achieve high QYs.