Engineering the Optical Properties of CsPbBr₃ Nanoplatelets through Cd²⁺ Doping

Lead halide perovskite nanoplatelets (NPls) attract significant attention due to their exceptional and tunable optical properties. Doping is a versatile strategy for modifying and improving the optical properties of colloidal nanostructures. However, the protocols for B-site doping have been rarely reported for 2D perovskite NPls. In this work, we investigated the post-synthetic treatment of CsPbBr₃ NPls with different Cd²⁺ sources. We show that the interplay between Cd²⁺ precursor, NPl concentrations, and ligands determines the kinetics of the doping process. Optimization of the treatment allows for the boosting of linear and nonlinear optical properties of CsPbBr₃ NPls via doping or/and surface passivation. At a moderate doping level, both the photoluminescence quantum yield and two-photon absorption cross section increase dramatically. The developed protocols of post-synthetic treatment with Cd²⁺ facilitate further utilization of perovskite NPls in nonlinear optics, photonics, and lightning.