dSiO₂@TiO₂-CsPbBr₃ hierarchical microspheres for dye-sensitized solar cells to enhance photovoltaic conversion efficiency

The hierarchical dSiO₂@TiO₂-CsPbBr₃ nanospheres (dST-CPB) have been successfully prepared by layer-upon-layer deposition of TiO₂ and CsPbBr₃ perovskite quantum dots on the dSiO₂ templates. dSiO₂@TiO₂ nanospheres (dST) promote dye adsorption due to the dendritic surface of SiO₂ (dSiO₂) with a large specific surface area (120 m² g⁻¹). The average size of dSiO₂@TiO₂-CsPbBr₃ is 1.4 μm, which provides superior light scattering ability compared with conventional microspheres. Based on the analysis of the photoelectric results, dST-CPB microspheres have the advantages of superior light absorption, tunable bandgap, and excellent electron mobility rate. The DSSC fabricated with dST-5%CPB and P25 has a short-circuit current density (14.3 mA cm⁻²), and photovoltaic conversion efficiency reached 7.1%, a 57.65% advancement compared to that of pure P25. The results show that the improved photovoltaic performance of dST-CPB-DSSC is mainly attributed to its unique microsphere structure and the synergistic effect of the TiO₂-CsPbBr₃ composite.