Pure nanobrookite titania (TiO2) thin films were deposited on glass substrates by the spin-coating method using titanium butoxide and acetic acid. The particle sizes of TiO2 films were controlled by heat treatment temperatures. The activation energy for particle growth was calculated as 23.1 kJ/mol. The structural and optical properties of the nanobrookite TiO2 thin films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), ultraviolet-visible absorption spectroscopy (UV-vis), and Fourier transform infrared spectroscopy (FTIR). (C) 2011 Elsevier B.V. All rights reserved.