Broader contextRecently, there has been a significant increase in interest in renewable energy due to growing concerns about global climate change and potential fossil fuel shortages. Solar energy is a renewable alternative to conventional energy sources. In order to lower the fabrication cost of solar energy conversion devices, people have been investigating dye-sensitized solar cells (DSCs), which can be fabricated using screen printing and low cost materials. To improve device efficiency, a TiCl4treatment for nanocrystalline TiO2films has been used to increase the current generation within the film. Although many articles on this method have been published, it still remains unclear why the TiCl4treatment increases the current generation. This paper is the first attempt to clearly prove the roll the TiCl4treatment plays in increasing the current generation using a back contact dye sensitized solar cell configuration sensitized with black dye. This configuration is suitable for addressing the TiCl4treatment effect because the electron transport and electron injection are more sensitive in this configuration than in conventional DSCs sensitized with bipyridyne dyes (N3, N719). The results of our experiment suggest that the TiCl4treatment increases electron transport and electron lifetime within the nanocrystalline TiO2film.