Effect of manganese ions concentration on the anatase–rutile phase transformation of TiO2 films

The phase structures of Ti1−xMnxO2 (0⩽x<0.08) films synthesized by sol–gel spin coating have been investigated. The effect of Mn dopants on the stability of titanium dioxide (TiO2) was studied by X-ray diffraction and Raman spectra for isochronally annealed samples. The increased Mn dopant concentration decreased the onset temperature of anatase–rutile (A–R) phase transformation. The calculated activation energy for the phase transformation decreased from 173.6 to 89.4 kJ/mol with Mn dopants concentration increasing from 0% to 7.51%. The Mn ions incorporated into the TiO2 lattice reduce the rutile nucleation barrier and promote the nucleation rate.