Chemically\nSpiraling CsPbBr₃ Perovskite\nNanorods

Abstract

Light emitting lead halide perovskite\nnanocrystals are currently\nemerging as the workhorse in quantum dot research. Most of these reported\nnanocrystals are isotropic cubes or polyhedral; but anisotropic nanostructures\nwith controlled anisotropic directions still remain a major challenge.\nFor orthorhombic CsPbBr₃, the 1D shaped nanostructures\nreported are linear and along either of the axial directions ⟨100⟩.\nIn contrast, herein, spiral CsPbBr₃ perovskite nanorods\nin the orthorhombic phase are reported with unusual anisotropy having\n(101) planes remaining perpendicular to the major axis [201]. While\nthese nanorods are synthesized using the prelattice of orthorhombic\nCs₂CdBr₄ with Pb­(II) diffusion, the spirality\nis controlled by manipulation of the compositions of alkylammonium\nions in the reaction system which selectively dissolve some spiral\nfacets of the nanorods. Further, as spirality varied with facet creation\nand elimination, these nanorods were explored as photocatalysts for\nCO₂ reduction, and the evolution of methane was also found\nto be dependent on the depth of the spiral nanorods. The entire study\ndemonstrates facet manipulation of complex nanorods, and these results\nsuggest that even if perovskites are ionic in nature, their shape\ncould be constructed by design with proper reaction manipulation.