Preparation of SnO ₂ Nanospheres and Its Application in Dye‐Sensitized Solar Cells

ABSTRACT In this work, a strategy is proposed to overcome the efficiency limitations of dye‐sensitized solar cells (DSSCs) through the hydrothermal construction of three‐dimensional SnO 2 nanosphere photoanodes. By investigating the influence of hydrothermal temperature on the morphology evolution, crystallinity, and optoelectronic properties of SnO 2 . The SnO 2 substrate synthesized at 160°C exhibits a well‐defined nanosphere morphology with an average diameter of approximately 500 nm, high crystallinity, and a wide bandgap of 3.67 eV, which collectively facilitate efficient charge separation and suppress carrier recombination. Furthermore, an ultrathin TiO 2 interfacial layer is introduced to construct a heterojunction architecture, thereby optimizing the interfacial energetics and accelerating charge transfer. As a result, the optimized device achieves a champion power conversion efficiency (PCE) of 4.23%, accompanied by a remarkably reduced charge‐transfer resistance of 12.91 Ω and an extended electron lifetime of 40.1 ms. Moreover, the device retains approximately 70% of its initial efficiency after continuous illumination for 30 days, demonstrating substantially improved operational stability. This work provides an effective strategy for overcoming the intrinsic limitations of SnO 2 photoanodes.