Ultra-robust spin-assisted infiltration for large-area, highly ordered, defect-free titanium dioxide and tin dioxide...

Thin-film optoelectronics leverage metal oxide inverse opal (IO) networks to simultaneously boost charge extraction and enhance light trapping; however, sol-gel routes commonly introduce unintentional defects such as cracks, nonuniform surfaces, and dense overlayers that limit device integration. Following this, we deliver an in-depth, mechanistically grounded approach that couples novel analytical modeling with empirical validations to study interstitial fluid flow dynamics and sol-gel drying behavior in infiltrated colloidal crystals to identify and resolve defect formation toward enabling high-performance IO applications. Modeling indicates that a spin-assisted infiltration strategy uniquely preserves uniform saturation during gel drying under near-zero finite stresses, thereby enforcing spatially uniform gelation-unachievable in conventional routes-which enables fabrication of large-area, crack-free infiltrated templates. Accordingly, a highly robust centrifugal force-based process window for infiltrating mechanically robust colloidal templates across titanium dioxide (TiO₂) sol concentrations is generated to ensure a uniform surface, suppress overlayer formation, and eliminate capillary pressure gradients through in-plane advective solvent evaporation, ultimately yielding large-area, highly ordered, defect-free inverse opal frameworks following calcination. Device demonstration for TiO₂ IO frameworks showcases improved specific detectivity in self-powered perovskite photodetectors compared to conventional nanostructures. Furthermore, the versatility of our approach is evidenced by fabricating high-quality photoconductive tin dioxide (SnO₂) nanoparticle-based inverse opal sensors capable of detecting weak ultraviolet-C (UV-C, 254 nm) light. This work establishes a mechanistic foundation for scalable, defect-free porous nanostructures across diverse materials for high-performance optoelectronic devices.