Effect of UV-activated TiO2 Nanoparticles on the Properties and Performance of PAni-TiO2 Nanocomposite Films for Solar Cell Applications

Abstract

Abstract To improve the performance of organic solar cells by enhancing the properties of the photoactivated nanocomposite layer, the UV irradiation process was used to activate titanium dioxide nanoparticles (TiO2 NPs). Herein, polymer solar cells were fabricated with FTO/(PAni-TiO2)/Ag system. A series of mixed polyaniline (PAni) with 20% of activated TiO2 NPs at different processing times was used to form PAni-TiO2 nanocomposite films. The structural evolution, surface characteristics, optical and electrical properties of PAni-TiO2 films have been investigated. XRD patterns showed that the UV treatment of TiO2 NPs increased the crystallite from 18.35 to 24.1 nm and the degree of crystallinity increased by 5.6%. The irradiated PAni-TiO2 films showed a rougher and more porous surface compared to the untreated one. Moreover, the adhesion force and electrical conductivity of the treated nanocomposite films at 8 h improved to be 137 mN/m and 6.62 S/m, respectively. Incorporation of activated TiO2 NPs exposure to UV for different times from 0 to 8 h with the PAni matrix enhanced the current density (Jsc) of PAni-TiO2 based nanocomposite solar cells from 3.11 to 4.83 (mA/cm2) and their efficiency from 0.33 to 0.85%. The increase in the solar cell efficiency is mostly ascribed to a structural change accompanied by a rapid increase in surface roughness, which led to a decrease in the reflected photons and thus an increase in the charge carriers produced. These results revealed the effect of surface UV irradiation of TiO2 NPs on their structural properties and the electronic contact between PAni and TiO2 NPs, which greatly influenced the amount of carrier transport within the PAni-TiO2 composites.