Preparation And Luminescence Propetries Of Eu³⁺ Doped TiO₂Nano/Micromateriats With Different Morphologies

In recent years, rare earth ions doped compounds have attracted extensiveresearch because of their significant importance in theory and application technology,and were widely used in high performance light-emitting devices, solar cells, solidstate laser, time resolution fluorescent labels for biological detection and otherfunctional material. The luminescent properties of the inorganic materials generallydepend on the size and morphology of the materials. As a main semiconductormaterial with wide band gap, TiO2has unique physical and chemical properties, richreserves, high chemical and thermal stability, excellent optical properties and wasnon-toxic. So far, a variety of rare earth doped TiO2with different morphologies havebeen successfully prepared. This paper takes TiO2as the matrix, successfully preparedEu3+doped TiO2nanorods, nanoparticles, microspheres, flowers and trees structureby hydrothermal method. Different morphologies of Eu3+doped TiO2werecharacterized by scanning and transmission electron microscope, X-Ray Diffraction,infrared spectroscopy, thermogravimetric and differential thermal analysis techniques.The morphologies, formation mechanisms and luminescent properties of these severalTiO2:Eu3+nano/micro luminescent materials were studied in detail. The followingsare the specific research results:：1. Eu3+doped TiO2microspheres were successfully synthesized by a one stephydrothermal method taking D-fructose as the capping agent. The preparation processis green and economy. The prepared TiO2: Eu3+microspheres were pure anatasephase, with uniform size and distribution. The diameter of the TiO2:Eu3+microspheres were about400nm before calcinations and of300nm after calcinations.The morphology, structure and formation mechanism of the synthesized TiO2:Eu3+microspheres were discussed in detail. Under ultraviolet excitation, the TiO2:Eu3+microspheres have strong red emission, and the strongest emission peak is located at612nm corresponding to5D0-7F2of Eu3+electric dipole transitions, which proved thatEu3+ions occupy the lack of anti symmetry sites in the TiO2lattice.2. TiO2:Eu3+nanorods, nanoparticles, and microspheres were preparedsuccessfully in CTAB/water/cyclohexane/pentanol system via a simple one-stephydrothermal method without calcination. The pH change of the microemulsion can regulate TiO2:Eu3+materials with controllable morphology. The TiO2:Eu3+microspheres were obtained under acidic conditions; TiO2: Eu3+nanoparticles wereobtained under neutral conditions; TiO2:Eu3+nanorods were obtained under alkalinecondition. TiO2:Eu3+materials with three kinds of morphologies are pure anatasephase with uniform size. Under ultraviolet excitation, TiO2:Eu3+with three kinds ofmorphologies of all showed red emission and luminescence intensity were I(nanorods)> I (microsphere)> I (nanoparticles).3. TiO2microspheres, microflowers, and microtrees were prepared by a simpleone-step hydrothermal method in hydrochloric acid solution. The morphology of themicron structures can be controlled by controlling the concentration of hydrochloricacid. The TiO2microspheres were prepared when the concentration of hydrochloricacid is3mol/L; the TiO2microflowers were prepared when the concentration ofhydrochloric acid is5mol/L; the TiO2microtrees were prepared when theconcentration of HCl is7mol/L. The TiO2microstructures were pure rutile phase withuniform size and dispersion. The formation mechanisms of titania with differentmorphologies were discussed.