Effect of crystallinity and morphology of TiO2 nano-structures on TiO2:P3HT hybrid photovoltaic solar cells

A comparative study has been made of hybrid solar cells based on poly(3-hexylthiophene) (P3HT) and different nano-structures of TiO2. Electrospinning, which is a low cost production method for large area nanofibrous films, was employed to fabricate TiO2 nanofibers and spin coating method was employed to fabricate organic-inorganic hybrid solar cells based on P3HT and TiO2 nanostructures. The performance of the hybrid solar cells was analyzed for four density levels of the TiO2 nanostructure. It was found that higher densities of TiO2 leads to more interface area and generates excitons, so that the power conversion efficiency increases to 0.13. TiO2 nanoparticles with power conversion efficiency of 0.15 showed better performance than TiO2 nanofibers because of greater interface area. Also the crystallinity effect of the TiO2 nanostructure on solar cell performance was investigated. Moreover, an improved photovoltaic performance was achieved after the interface modification, and the highest conversion efficiency was obtained from the N719 modified device at 241 nm, short-circuit photocurrent (J sc) of 3.88 mA cm−2, open-circuit voltage (V oc) of 0.09 V and fill factor of 0.16; so that an overall conversion efficiency (η) of 0.35% was obtained.