1D ZnO nanorods for energy conversion applications

Abstract

ZnO, the direct wide bandgap semiconductor, crystallizes in three major structures of rock-salt, zinc-blende, and wurtzite. This versatile material has a band gap of around 3.2-3.6 eV and is transparent to visible light. With properties such as high diffusion coefficient, large electron mobility, and ease of processing, they are extensively used in optoelectronic applications such as solar cells, photocatalysis, light emitting diodes, and field emission, etc. Growth of nanostructured ZnO bridges the gap between micro and nano worlds. In this work, one dimensional ZnO was grown by seed assisted hydrothermal method. Seeds of ZnO particles were synthesized using Zinc Acetate and Potassium hydroxide and were spin-coated over the substrate. Further, ZnO nanorods were grown over seed coated fluorine-doped tin oxide substrates. On varying the growth parameters such as initial concentration and temperature, the dimensions of the ZnO nanorods were controlled. It is demonstrated that precursor concentration has great influence over the diameter of nanorods while the length of nanorods changeswith respect to reaction time. Effect of length of nanorods over its optoelectronic properties has also been analyzed. Various characterization techniques like XRD, EDS, XPS, UV-Visible, and PL spectroscopy was used to study the structural and optical properties of the synthesized one dimensional ZnO nanorods. Apart from growing ZnO nanostructure on fluorine-doped tin oxide substrates, the growth of one dimension ZnO over p-type single crystal silicon substrate was developed. Additionally, the performance of one-dimensional ZnO nanorods was examined for its application as photoanodes in perovskite solar cell, and their photoresponse has been analyzed.