Precursor-Free Photoelectrochemical Fabrication of Spiral Lead Oxide Nanostructures under Circularly Polarized Light

Chiral nanostructures have attracted considerable attention because of their strong interactions with circularly polarized light (CPL) and their various applications. Although various fabrication methods have been reported, photoelectrochemical approaches using CPL as the chiral source are attractive because of their simplicity, cost-effectiveness, and scalability. However, previous CPL-based methods have required two or more steps, including the preparation of anisotropic precursors. Here, we demonstrate a single-step method for the selective growth of chiral PbO2 nanostructures with handedness dictated by CPL at a chiral yield of 87%, by simply irradiating a transparent electrode with CPL, without using precursor nanoparticles. The obtained structures exhibit well-defined spiral morphologies and high chiroptical activity with maximum dissymmetry factors (g-factors) ranging from 0.006 to 0.010. This conceptual framework, involving symmetry breaking through random nucleation and Mie-resonance-mediated spiral growth under CPL, may be applicable to the template-free fabrication of various chiral nanomaterials.