In-situ fabrication of dual porous titanium dioxide films as anode for carbon cathode based perovskite solar cell

We develop a dual porous (DP) TiO₂ film for the electron transporting layer (ETL) in carbon cathode based perovskite solar cells (C-PSCs). The DP TiO₂ film was synthesized via a facile PS-templated method with the thickness being controlled by the spin-coating speed. It was found that there is an optimum DP TiO₂ film thickness for achieving an effective ETL, a suitable perovskite/TiO₂ interface, an efficient light harvester and thus a high performance C-PSC. In particular, such a DP TiO₂ film can act as a scaffold for complete-filling of the pores with perovskite and for forming high-quality perovskite crystals that are seamlessly interfaced with TiO₂ to enhance interfacial charge injection. Leveraging the unique advantages of DP TiO₂ ETL, together with a dense-packed and pinhole-free TiO₂ compact layer, PCE of the C-PSCs has reached 9.81% with good stability.