Titanium dioxide is a wide band‐gap semiconductor of high chemical stability, nontoxicity and large refractive index. Because of the high photocatalytic activity, anatase is a preferred TiO2 form in many applications such as for air and water splitting and purification. Doping of TiO2 with various ions can increase the photocatalytic activity by enhancing light absorption in visible region and can alter structure, surface area and morphology. Also, by doping TiO2 with optically active ions, visible light via up‐ or downconversion luminescence can be produced. It is a challenge to optimize the synthesis procedure to incorporate rare earth RE3+ ions into the TiO2 structure due to large mismatch in ionic radii between the Ti4+ and RE3+ and because of the charge imbalance. Visible (VIS) and ultraviolet (UV) luminescence of several RE3+ ions can be obtained when incorporated into anatase TiO2, also affecting microstructural characteristics of TiO2. It is of great importance to summarize publications on rare earth‐doped anatase TiO2 nanoparticles to find correct TiO2-RE combination to sensitize trivalent rare earths luminescence, as well as to predict or tune structural and morphological properties. A better understanding on these topics may progress the desired design of this kind of material towards specific applications.
Part of the book: Titanium Dioxide