A facile and low-cost fabrication of TiO2 compact layer for efficient perovskite solar cells

• Various TiO2 compact layers as electron transport layers have been fabricated by either a spin-coating or dip-coating method.
• Comparative investigation of organolead halide perovskite solar cells with different TiO2 compact layers has been done.
• Efficiency was significantly improved by using the dip-coating based TiO2 compact layer.
• A possible route towards low-cost and large area perovskite solar cells.

A uniform and compact hole blocking layer is necessary for high efficient perovskite-based thin film solar cell. In this study, we fabricated TiO2 compact layers by using a simple dip-coating method in contrast to the widely used techniques such as spin coating and spray pyrolysis. In this study, we optimized the surface morphologies of dip-coating based TiO2 compact layers by controlling the concentration of Ti precursor solution diluted in ethanol. The analyses of devices performance characteristics showed that thickness and surface morphologies of different TiO2 compact layers played a critical role in affecting the efficiencies. The dip-coating route to prepare TiO2 compact layers employed in this study is more amenable to fabricate the large area device and less expensive.