The electron transport layer (ETL) of organic–inorganic perovskite solar cells plays an important role in their power conversion efficiency (PCE). In this study, TiO₂ hollow nanospheres with a diameter of 150 nm were prepared by a facile synthesis method. The synthesized TiO₂ hollow nanospheres had a highly porous structure with a surface area of 85.23 m² g⁻¹, which is significantly higher than commercial TiO₂ (P25) (54.32 m² g⁻¹), indicating that they can form an ideal mesoporous layer for Formamidinium iodide-based perovskite solar cells (PSCs). In addition, the nanospheres achieved a remarkable perovskite performance, and the average PCE increased from 12.87% to 14.27% with a short circuit current density of 22.36 mAcm⁻², an open voltage of 0.95 V, and a fill factor of 0.65. The scanning electron microscopy images revealed that the enhanced PCE could be due to the improved carrier collection and transport properties of the nanosphere, which enabled efficient filtration of perovskite into the TiO₂ mesoporous ETL. The TiO₂ hollow nanospheres fabricated in this study show high potential as a high-quality ETL material for efficient (FAPbI₃)_0.97(MAPbBr₃)_0.03-based PSCs.