Preparation of c-TiO₂ films; Preparation of TiO₂NSs films; SEM Images; J-V characteristic; Tables from Enhanced photovoltaic properties of perovskite solar cells by TiO₂ homogeneous hybrid structure.

The c-TiO₂ films were deposited onto the clean FTO by chemical bath deposition (CBD) method with 0.06 M TiCl₄ aqueous solution at 70 ℃ for 30 min. The c-TiO₂ films were annealed at 450 ℃ for 30 min in ambient conditions.; TiO₂NSs films were fabricated by a hydrothermal method; Fig. S1 Top-view images of TiO₂NSs on FTO/c-TiO₂ prepared at 170 ℃ for (a) 1 h; (b) 2 h; (c) 3 h; (d) 4 h, the scale bar is 500nm. Fig. S3 (a) Top-view image of 7C TiO₂NPs on FTO/c-TiO₂; (b) the enlarged view of TiO₂NPs; (c) cross-sectional SEM image of 7C TiO₂NPs on FTO/c-TiO₂.;Fig. S2 J-V characteristic of the lead iodide perovskite solar cells based on TiO₂NSs films of different reaction time. Fig. S4 J-V characteristic of the lead iodide perovskite solar cells based on 3h TiO₂NSs/7CNPs and 7C NPs films.; Table. S1 Photovoltaic Device Parameters of the TiO₂NSs/CH₃NH₃PbI₃ Solar Cells. Table. S2 Photovoltaic Device Parameters of the FTO/c-TiO₂/TiO₂NSs/NPs/CH₃NH₃PbI₃/HTM/Ag and FTO/c-TiO₂/TiO₂NPs/CH₃NH₃PbI₃/HTM/Ag Solar Cells.