Architectural transformation of the nanoparticle superstructures induced by ultraviolet light irradiation and their application in photoelectrochemical switch devices

The studies of the self-assembly processes of nanoparticles (NPs) will benefit the understanding of both the fundamental properties of nanomaterials and the bottom-up fabrication technologies at nanoscales. The NPs can self-assemble into complex microscale structures, which have been reported and attracted increasing attention in recent years. In this paper, a kind of bowknot-shaped structure formed from the individual (CdS)/CdTe NPs has been fabricated. Interestingly, the bowknot structure twists upon ultraviolet (UV) light irradiation. Special multiparticle assemblies of the double-flower-shaped structures are identified. The structural transformation process could be attributed to photocorrosion of CdS under the UV light. The bowknot-shaped topotactic structure is also important for the transformation of NP superstructures (NP-S). These results indicate that the photoetching technique could adjust the transformation among different NP superstructures, which offers a new method to fabricate novel NP-S. Both irradiated and unirradiated NP-S have been applied in photoelectrochemical devices to verify the photovoltaic effect.