Effect of TiO₂ Thin Film Morphology on Polyaniline/TiO₂ Solar Cell Efficiency

Nanocrystalline titanium dioxide (TiO₂) thin films were prepared by using sol-gel through spin- coating method. An assembly of indium tin oxide (ITO)/TiO₂/polyaniline (PANI)/Ag was made in a sandwich panel structure. The obtained junction shows rectifying behavior. Additionally, the I/V characteristic indicates that a P-N junction at nanocrystalline PANI/TiO₂ interface has been created. In this experimental study, we depended only on the ratio between titanium and PANI in the process of preparing sol-gel (PANi/TiO₂ at 20% wt). The largest open circuit voltage of 656 mV and short current density of 0.00315 mΑ/cm² produce 0.0004% power conversion solar cell (η) under simulated solar radiation (50 mW/cm²). The thin films of PANI and titanium oxide (TiO₂)/ PANI composites were synthesized by sol-gel technique. Pure TiO2 powder with nanoparticle size of less than 25 nm and PANI were synthesized through chemical oxidative polymerization of aniline monomers. The composite films were characterized by high resolution X-ray diffraction, Fourier transform infrared spectroscopy, field effect scanning electron microscopy, and UV-vis spectroscopy. The results were compared with the corresponding data on pure PANI films. The intensity of diffraction peaks for PANI/TiO₂ composites is lower than that for TiO₂. The characteristic of the FTIR peaks of pure PANI shifts to a higher wave number in TiO₂/PANI composite, which is attributed to the interaction of TiO₂ nanoparticles with PANI molecular chains.