Broadband Optical Absorption Enhancement in Hybrid Organic-Inorganic Perovskite Metasurfaces

Hybrid organic-inorganic perovskite (HOIP) becomes attractive due to its high refractive index and excellent electrical properties. Recent demands of ultrathin materials for photoelectric battery and skin-like sensors especially require high optical absorption, which is difficult for conventional homogeneous thin films. In this work, by introducing nanohole arrays on HOIP ultrathin film, we achieve all-dielectric HOIP metasurfaces with broadband optical absorption enhancement. Based on the finite-difference time-domain method, we show that Mie resonances occur in the HOIP metasurfaces, which depend on the surface structure, including the nanohole geometry and the spatial periodicity. Consequently, the absorption can be tuned by the nanohole arrays on the HOIP film. Compared with the flat HOIP film, significant absorption occurs in the HOIP metasurface over entire visible regime. An assembly of nanoholes are designed and we achieve broadband absorption from 51% to 87% in the wavelength range of 400-770nm, and the external quantum efficiency of the solar cell with this HOIP metasurface can be 44% higher than that of a flat HOIP film. We suggest that these results are inspiring for effective light trapping and efficient photoelectric conversion with ultrathin HOIP metasurfaces.