Fig. 1. Principle of process and interference light field distribution. (a) Principle of lithography; (b) principle of two-beam laser interference lithography; (c) two-beam laser interference light field distribution

Fig. 2. Preparation process of micro-nano composite structure and microscope photos of masks with different patterns. (a) Preparation process of micro-nano composite structure using lithography combined with two-beam laser interference lithography;(b) strip; (c) rectangular lattices; (d) circular lattices; (e) hexagonal lattices

Fig. 3. AFM images. (a) Composite structure with micro-strip grating and nano-grating in parallel orientation; (b) composite structure with micro-strip grating and nano-grating in vertical orientation; (c) composite structure with micro-rectangular lattices combined with nano-grating; (d) composite structure with micro-circular lattices combined with nano-grating; (e) composite structure with micro-hexagonal lattices combined with nano-grating

Fig. 4. AFM images of composite structures with nano-grating combined with micro-gratings with different periods. (a) 4 μm; (b) 5 μm; (c) 6 μm

Fig. 5. AFM images. (a) Strip-grating with period of 2 μm; (b) composite structure with nano-grating and micro grating with period of 2 μm in parallel orientation; (c) composite structure with nano-grating and micro grating with period of 2 μm in vertical orientation

Fig. 6. Structural diagram of IMI and absorption spectra of CH3NH3PbI3 in IMI structure. (a) Structural diagram of IMI with micro-nano composite grating; (b) absorption spectra of CH3NH3PbI3 in IMI structures with different gratings