Preparation and Optical Properties Study of Low-layer Inverse Opal Photonic Crystal Thin Films

A low-layer SnO₂ photonic crystal thin film with an inverse opal structure was constructed in this study. Based on the unique ordered porous structure and slow photon effect of inverse opal photonic crystal materials, it effectively enhances light absorption and plays a significant role in fields such as solar cells and photocatalysis. In this study, three sizes of polystyrene (Polystyrene, PS) microspheres were prepared using a soap-free emulsion polymerization method, with controlled amounts of monomers and initiators. A small amount of sodium dodecyl sulfate (Sodium Dodecyl Sulfate, SDS) was added dropwise to the dispersion solution during vertical deposition self-assembly to prepare low-layer PS opal templates. Finally, a low-layer SnO₂ inverse opal photonic crystal film was obtained using a sacrificial template method. Compared with planar structures, this film exhibits enhanced light absorption and diffuse reflectance while maintaining a higher specific surface area within the visible wavelength range. The inverse opal photonic crystal film provides a new strategy for designing electron transport layers in perovskite solar cells.