Smart Mn(7+) Sensing via Quenching on Dual Fluorescence of Eu(3+) Complex-Modified TiO(2) Nanoparticles

In this work, titania (TiO(2)) nanoparticles modified by Eu(TTA)(3)Phen complexes (ETP) were prepared by a simple solvothermal method developing a fluorescence Mn(7+) pollutant sensing system. The characterization results indicate that the ETP cause structural deformation and redshifts of the UV-visible light absorptions of host TiO(2) nanoparticles. The ETP also reduce the crystallinity and crystallite size of TiO(2) nanoparticles. Compared with TiO(2) nanoparticles modified with Eu(3+) (TiO(2)-Eu(3+)), TiO(2) nanoparticles modified with ETP (TiO(2)-ETP) exhibit significantly stronger photoluminescence under the excitation of 394 nm. Under UV excitation, TiO(2)-ETP nanoparticles showed blue and red emission corresponding to TiO(2) and Eu(3+). In addition, as the concentration of ETP in TiO(2) nanoparticles increases, the PL intensity at 612 nm also increases. When ETP-modified TiO(2) nanoparticles are added to an aqueous solution containing Mn(7+), the fluorescence intensity of both TiO(2) and ETP decreases. The evolution of the fluorescence intensity ratio (I(1)/I(2)) of TiO(2) and ETP is linearly related to the concentration of Mn(7+). The sensitivity of fluorescence intensity to Mn(7+) concentration enables the design of dual fluorescence ratio solid particle sensors. The method proposed here is simple, accurate, efficient, and not affected by the environmental conditions.