ZnO nanopinecone arrays with enhanced photocatalytic performance in sunlight

Abstract

A novel ZnO nanopinecone was fabricated by a wet chemical approach in an aqueous solution of ascorbic acid. The ZnO nanorod layer facilitated the growth of aligned nanopagodas, stacking nanoplates, and nanopinecones. The correlation between the concentration of zinc precursor (zinc nitrate and HMTA) and L-ascorbic acid was exploited to control the morphologies of ZnO nanostructures for the same reaction conditions. The complex ZnO nanostructures exhibited very strong and sharp ultraviolet emissions from the band gap, while almost no green emission was attributed to singly ionized oxygen vacancies in the cathodoluminescence spectra. ZnO nanopinecones can provide a higher surface-to-volume ratio and better stability against aggregation with more polar surface exposure, resulting in their highest photocatalytic performance in sunlight. The ZnO nanopinecone arrays are beneficial in fabricating novel devices, such as ultraviolet lasers, light-emitting devices, and dye-sensitized solar cells.