Ultra-robust spin-assisted infiltration for large-area, highly ordered, defect-free titanium dioxide and tin dioxide inverse opal frameworks toward efficient ultraviolet-visible photodetection

초록

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 indepth, 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 nano structures across diverse materials for high-performance optoelectronic devices.

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