Three-dimensional self-branching anatase TiO₂ nanorods with the improved carrier collection for SrTiO₃-based perovskite solar cells

The organic–inorganic perovskite solar cells based on ternary oxide SrTiO₃ shows a higher Voc, attributed to its slightly higher conduction band edge and better morphology of absorber material. However, its less efficient carrier collection and limited overall interfacial areas between the absorber material and the electron-transport layer (ETL), dramatically reducing the Jsc. Here, By adjusting the concentrations of the Ti(OBu)₄, we successfully prepared the three-dimensional (3D) self-branching anatase TiO₂ nanorod/SrTiO₃ nanocomposites, and slightly tuned the particle size of SrTiO₃. With the incorporation of the three-dimensional (3D) self-branching anatase TiO₂ nanorod, the Jsc of the device based on SrTiO₃ was highly boosted. The best performing solar cell we obtained exhibited a PCE of 9.99% with a Jsc of 19.48 mA/cm². The excellent performance could be ascribed to the improvement of charge carrier collection of SrTiO₃, better surface coverage and crystallinity of CH₃NH₃PbI₃, and enhanced light scattering ability caused by 3D self-branching anatase TiO₂ nanorods. - Highlights: • The three-dimensional (3D) self-branching anatase TiO₂ nanorod/SrTiO₃ nanocomposites were prepared. • The particle sizes of SrTiO₃ can be slightly tuned. • The best performing solar cell we obtained exhibited a PCE of 9.99% with the Jsc of 19.48 mA/cm².