Hydrothermal growth of ZnO nanowire arrays: fine tuning by precursor supersaturationElectronic supplementary information (ESI) available: Inconsistencies of one-pot hydrothermal growth; packing density of ZnO nanowires; the UV-vis spectroscopy method for nanoscale materials; multiple linear regression results for the relationship between nanowire geometry and photocurrent. See DOI: 10.1039/c6ce02368a

• Main Authors: Yan, Danhua, Cen, Jiajie, Zhang, Wenrui, Orlov, Alexander, Liu, Mingzhao
• Format: Journal Article
• Language: English
• Published: 16.01.2017
• ISSN: 1466-8033
• DOI: 10.1039/c6ce02368a

Here we develop a technique that fine tunes the hydrothermal growth of ZnO nanowires to address the difficulties in controlling their growth in a conventional one-pot hydrothermal method. In our technique, precursors are separately and slowly supplied with the assistance of a syringe pump, through the entire course of the growth. Compared to the one-pot method, the significantly lowered supersaturation of precursors helps eliminating competitive homogeneous nucleation and improves the reproducibility. The supersaturation degree can be readily tuned by the precursor quantity and injection rate, thus forming ZnO nanowire arrays of various geometries and packing densities in a highly controllable fashion. The precise control of ZnO nanowire growth enables systematic studies on the correlation between the material's properties and its morphology. In this work, ZnO nanowire arrays of various morphologies are studied as photoelectrochemical (PEC) water splitting photoanodes, in which we establish clear correlations between the water splitting performance and the nanowires' size, shape, and packing density. Novel syringe-pump assisted hydrothermal growth fine tunes ZnO nanowire arrays into the desired morphology by precise control of supersaturation.