Strong photoluminescence emission of Eu:TiO2 nanotubes

Three nanostructured (nanocrystals, nanotubes and nanorod) Eu:TiO2 samples synthesized by a sol–gel method with chemical treating are measured by TEM and photoluminescence spectroscopy. The photoluminescence intensity of Eu:TiO2 nanotubes is the strongest among the three nanostructured samples and is clearly visible by naked eyes, which is about five times of that of Eu:TiO2 nanocrystals. The emission mechanism is proposed in this article.