We will present interesting nano-engineered materials, ZnO nanocones (NCs) and their recent progress made in our group. The morphology of ZnO nanostructures was engineered to demonstrate enhanced optical and electrochemical characteristics of ZnO NCs compared to ZnO nanowires (NWs). ZnO NCs are obtained by chemically etching ZnO NWs. Hence, the morphological effects on various physical properties can be directly compared between NCs and NWs. In recent work of ours, electrochemical characteristics of ZnO NCs and NWs are extensively investigated to demonstrate morphology dependent capacitive performance of one dimensional ZnO nanostructures. Cyclic voltammetry measurements on these two kinds of electrodes in a three-electrode cell confirms that ZnO NCs exhibit a high specific capacitance of 378.5 F g−1 at a scan rate of 20 mV s−1, which is almost twice that of ZnO NWs (191.5 F g−1). In addition, ZnO NCs demonstrated enhanced optical properties, in particular much lower reflectance compared to NWs. We observed that optical properties are much enhanced from NCs compared to NWs. These observations suggest that ZnO NCs can be used main active materials for optical and energy devices.
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