Fig. 1. Schematic diagram of nano trapping²⁴: (a) Schematic diagram of nano-trapping structure^[24]; (b) Mie resonance; (c) low-quality-factor Fabry-Perot standing-wave resonance; (d) guided resonance; (e) diffracted modes.

Fig. 2. Structure and performance of perovskite cell made byTavakoli^[36] form Department of electronic and computer engineering, Hong Kong University of science and technology³⁶: (a) Schematic structure of the perovskite solar cell device with nanocone PDMS film attached on the top and flexible glass substrate/tin doped oxide transparent electrode/zinc oxide/perovskite/spiro OmeTAD/gold; (b) QE measurement of perovskite devices with and without a PDMS nanocone film; Electric field in the active layer (c) without and (d) with PDMS nanocone film with red showing a high generation rate and blue showing a low generation rate.

Fig. 3. The structure and performance of perovskite cell made by Dr.Shi of our group^[40] of our research group: (a) Schematics of possible incident light paths within perovskite solar cells with textured substrate; (b) surface morphologies of SEM images oftextured FTO/TiO₂/perovskite film; (c) surface morphologies of SEM images ofsmooth FTO/TiO₂/perovskite film; (d) absorption coefficient of different perovskite films without/with Au back contact; (e) performance of devices with different FTO substrates. J-V characteristics.

Fig. 4. Structure and performance of perovskite battery devices made by Huang et al from Department of Materials Engineering, Monash University^[43]: (a) Schematic diagram illustrating the fabrication procedure (b) centred dark-field TEM image for a cross-section of a textured perovskite sample deposited on FTO-glass; (c) IPCE spectrum (solid lines) of a planar perovskite device (grey line) and a textured.

Fig. 5. Material structure and light trapping properties ofSeong^[45], Department of mechanical and aerospaceengineering, Seoul National University (a) 3D illustration of moth-eye patterned mesoporous TiO₂ (mp-TiO₂) layer; (b) electric field on active layer with Moth-eye TiO₂.

Fig. 6. Trapping principle diagram of perovskite devices made byPascoe^[50], Department of materials science andengineering, Monash University: (a) Near-field Enhanced Surface Plasmon Resonance of Metal Nanoparticles Embedded near the Absorp-tion Layer; (b) surface plasmon nanostructures with periodic structures.