Characterization of AI-doped TiO₂ thin film synthesized via sol-gel method for solar cell application

The scope of this research is to synthesize and characterize a TiO₂ thin film to be used in solar cell application. The Al-doped TiO₂ thin film was synthesized via the sol-gel method. The sample produced was characterized using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). These XRD characterization was conducted to determine the aluminum bond on the surface of the Al-doped TiO₂ while the FT-IR characterization was used to determine the functional group present. FT-IR spectra of Al-doped TiO₂, titania precursor and alumina source is illustrated in Fig. 1. The 3000 cm-1 band was attributed to the hydroxyl group from water and ethanol occluded in the titania pore. The OH bending band of water in gel was observed at 1600 cm-1 while the O-Ti-O band was observed at 1400 cm-1. The presence of additional peaks indicated the dispersion of doping ions was not efficient. By comparison with the alumina dopant, the bands at 1300 cm-1 was attributed to Al-O bonds. The results obtained from the XRD analysis were inconclusive due to the sample exhiiting a wet nature when prepared for the XRD analysis. The XRD analysis should indicate a peak around 25º for the formation of the anatase phase of Al-doped TiO₂ thin film.