The influence of drying conditions on some physical–chemical properties of TiO2-based layers prepared using different organic binders

The TiO2 thin layers were obtained using different organic binders: glycerol, methylcellulose, polyethylene glycol and polyvinyl alcohol. The samples were freeze or heat dried, and then annealed at 500 °C for 1 h. X-ray diffraction patterns showed the presence of TiO2-anatase phase and a poor crystallinity of thin layers. IR microscopy images displayed a homogeneous surface without cracks and without particles agglomeration in case of all samples. Pore size distribution estimated by N2 physisorption revealed the freeze-dried samples with larger pores than the heat-dried ones. The TiO2 thin layers dried in freeze conditions present lower absorbance intensities, but lower values of band gap energy with a positively effect on the optical sensitivity of TiO2 for visible light region. The fluorescence spectral features show no obvious distinctions. The results show that each of these organic additives can act as active binders to obtain uniform crack-free TiO2-based layers and the drying method plays a significant role to promote all final materials as potential candidates for various optical applications.