Photoluminescence and Photocatalysis Properties of Dual-Functional Eu3+-Doped Anatase Nanocrystals

Red-color-emitting TiO2:Eu3+ nanophosphors have been synthesized through the hydrothermal process. Samples with different morphologies have been obtained by changing pH values of solution. The structural and luminescence properties of samples were investigated through scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–vis spectra, and photoluminescence (PL) spectra. Most importantly, surface photovoltage spectra were used to discuss the charge transfer process and further explained the luminescence phenomenon of different morphologies for the first time. The critical transfer distance for the Eu3+ ions in TiO2 matrix was calculated, and we could conclude that the concentration quenching process was attributed to the multipole–multipole interaction. The relative intensity ratios of 5D0–7F2 transition to 5D0–7F1 transition of TiO2:x%Eu3+ (x = 2, 4, 6, 8, 10, 12) have been calculated to understand the lattice symmetry and coordination environment of Eu3+ ions. The spectral characteristics and si...