Preparation and Characterization of Multi-Morphological and Multi-Periodical Micro-Nano Composite Structures

In this study, the micro-nano composite structures having multiple morphologics and periods were fabricated via conventional ultraviolet photolithography combined with two-beam laser interference lithography and two-step exposure via two-beam laser interference lithography. The micro nano composite structure could overcome the shortages imposed by conventional laser photolithography, which yields the microstructures with single morphology and period. By optimizing the experimental parameters, the micro-nano composite structures having different nano-gratings, such as micro-strip gratings, rectangular lattices, circular lattices, and hexagonal lattices, were fabricated. By incorporating the micro-nano composite grating in glass/Ag film/CH3NH3PbI3, the absorption of CH3NH3PbI3 is enhanced in the visible range. This enhancement is mainly attributed to the coaction of light scattering of micro-grating and electric field enhancement of surface plasmon polaritons at the Ag film/CH3NH3PbI3 interface.