Bioinspired synthesis of vertically aligned ZnO nanorod arrays: Toward greener chemistry

We developed a green, low-cost, bioinspired aqueous synthesis method to fabricate one-dimensional (ID) vertically aligned ZnO nanorod arrays on zinc substrates at room temperature. Scanning electron microscopy images, transmission electron microscopy images, and energy-dispersive X-ray spectrum show densely well-aligned single-crystal ZnO nanorod arrays with a length of ̃400 nm fabricated by a simple method. Further, we reveal a growth mechanism that continuously deposits the freshly formed ZnO onto the zinc substrates, which results from the reaction between Zn²⁺ coordinated with cysteine and its derivatives and OH- in base solution, and leads to forming ZnO nanorod arrays. More importantly, the simple preparation can grow hierarchical structures of ZnO nanorod arrays as well as fabricating the arrays on different types of zinc-based substrates. Finally, the paper reports as-prepared ZnO nanorod arrays repeatedly photobleach Rhodamine 6G, and the results suggest the photobleach efficiency increases significantly due to the arrays.