Advances on the Applications of Nanostructured Composites Zinc Oxide (Zno) in Solar Energy Devices, And Photocatalysis: A Review

Due to global efforts to achieve energy sustainability, researchers across the world are interested in new materials that can improve energy generation and storage, especially through the application of metal oxides. This review focuses on the recent advances in the applications of composite nanostructured ZnO in solar energy devices, and photocatalysis. Different solar energy generation and storage devices (dye-sensitized solar cells, perovskite solar cells, lithium-ion batteries, and supercapacitors) were studied. Among other metal oxides, the vast potential application of nanostructured ZnO in solar energy devices is due to its excellent bandgap energy, high level of electron mobility, measurable room-temperature, luminescence, low cost and non-toxicity. High theoretical capacity of ZnO makes it an outstanding material for fabrication of lithium-ion batteries. More so, the biocompatible, and environmentally friendly properties of ZnO enable it to have favorable applications in photocatalysis. Understanding the method of synthesizing ZnO nanostructures is important to optimize its applications in different areas; hence we briefly explained a few synthesis methods. Specifically, we discussed chemical vapor deposition, chemical bath deposition, electrodeposition, and hydrothermal methods. Though we suggested in this review that the gas phase method works better. This is because it produces layers and nanostructures of the best quality and device heterostructure, but it is expensive and requires high knowledge to operate. A table showing the pros and cons of all the methods discussed was presented to help researchers to decide on the method to use when synthesizing ZnO nanostructures. But regardless of the method used, the nature of ZnO nanostructures formed depends on the deposition temperature.