Emission of TiO2:Y3+ and Eu3+ in water medium, under UV excitation and band gap theoretical calculus

Ti1-xYxO2:Eu3+ luminescence materials were prepared via conventional sol-gel process and heat treated at 700 degrees C for 8 h, in an air atmosphere. The Eu3+ concentration was fixed as 3.0 mol%, and the proportion amount between Ti4+:Y3+ was fixed in: 1:0; 0.9:0.1; 0.8:0.2; 0.7:0.3; 0.6:0.4, and 0.5:0.5 in mol%. The luminescent materials were characterized by X-ray powder diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Raman, and UV excited photoluminescence. The materials display intense reddish color under UV excitation, due to the intraconfigurational 4f transitions from Eu3+ ion, even when suspended in water solution at room temperature. The non-radiative energy transfer processes from the O -> Eu Ligand Metal Charge Transfer states to the intra-configurational 4f exciting levels of Eu3+ ion are being reported. The theoretical band gap value obtained by semi-empirical PM7 based on the Rietveld refinement results showed that the values are consistent with TiO2 reported in the literature, indicating that the material reported here is suitable for use as Eu3+ host. Furthermore, CIE parameters are discussed to characterize the monochromatic profiles of color emission. The materials ob-tained in this work showed intense emission in the red region, even when suspended in aqueous medium. Based on the results observed, these luminescence materials may be potential candidates for red light emitting diodes, biological markers, and solid-state lighting.

Automated summary

Ti1-xYxO2:Eu3+ luminescence materials were prepared using the sol-gel method and heat treated. The luminescent properties and energy transfer processes were studied, showing intense reddish color emission under UV excitation, even in a water solution. The theoretical band gap value indicated that the material is suitable for Eu3+ hosting. These luminescence materials have potential applications in red light emitting diodes, biological markers, and solid-state lighting.