Giant Chirality in Hybrid Perovskite Metasurfaces via a Universal van der Waals Dry Transfer Strategy

Abstract Metal halide perovskites lack intrinsic chirality because of their high structural symmetry, a challenge that can be addressed by employing chiral metasurfaces. However, conventional lithography involves the use of solvents such as photoresist and acetone, which are incompatible with the solvent-sensitive nature of perovskites. Here, we propose a nondestructive van der Waals dry transfer strategy to integrate gold windmill-shaped nanostructures onto perovskite films, avoiding solvent damage. The resulting metadevices exhibit giant optical chirality in the near-infrared region, with experimental circular dichroism (CD) and anisotropy factor reaching up to 7000 mdeg while the optimized size-scaled structure reaches a maximum CD of 12,000 mdeg with an anisotropy factor of 0.7, respectively, achieving a 2 orders of magnitude enhancement over the intrinsic response. Simulations reveal that the strong chirality originates from the spatial interference between electric multipoles and magnetic dipoles. Moreover, the peak wavelength and intensity of the chiral response can be flexibly manipulated by adjusting the structure size, and the strategy can be applied to various perovskite systems. Our work provides a universal route for constructing chiral perovskite devices with promising applications.