Effect of polyethylene glycol on porous transparent TiO2 films prepared by sol–gel method

Multilayered titania (TiO2) films have been prepared via sol–gel dip-coating method from a tetraethyl-orthotitanate solution that contains 2 g of polyethylene glycol (PEG) with different molecular weight (6000, 20,000 and 35,000). The films were deposited on fluorine doped tin oxide (FTO) coated glass and annealed by a thermal treatment at 450 °C for 30 min. We demonstrated how the structure, the morphology and the optical properties of the films can be controlled by varying the PEG molecular weight and number of depositions. The correlation between these parameters and the film properties was investigated. Sol–gel deposited and PEG doped TiO2 films demonstrate better properties for their use in solar cell applications, by enhancing the transmittance value in the 380–540 nm range.