Broadband optical absorption enhancement in hybrid organic–inorganic perovskite metasurfaces

The hybrid organic–inorganic perovskite (HOIP) becomes a promising candidate for ultra-thin photoelectric batteries and skin-like sensors. However, homogeneous thin films of the material usually provide low absorption efficiency. In this work, by engineering the nanohole arrays on a HOIP ultrathin film, we successfully design an all-dielectric HOIP metasurface with broadband optical absorption enhancement through the finite-difference time-domain technique. The absorption enhancement arises from the Mie resonance, which can be tuned by varying the geometrical parameters and the spatial periodicity of the nanoholes. Compared with a uniform HOIP film, the HOIP metasurface significantly enhances the absorption over the entire visible regime, and the maximum absorption rate reaches 90%. Moreover, our design with multiple nanohole sizes provides consistently high absorption efficiency up to 51%–87% in a broad wavelength range of 400 nm–770 nm. Furthermore, the external quantum efficiency of a solar cell with our HOIP metasurface is 44% higher than that of a uniform HOIP film by assuming the ideal process with infinite carrier lifetime and negligible recombination. Our findings may provide a route for effective light trapping and efficient photoelectric conversion with ultrathin HOIP metasurfaces.