Growth of 2D ZnO Nanowall for Energy Harvesting Application

Here we report a novel and facile way to grow the vertically aligned ZnO nanowall on both sides of the flexible substrate through low- temperature, cost-effective hydrothermal method and their application toward energy harvesting application. The fabricated nanogenerator device structure consists of a ZnO nanowall structure on the both sides of the flexible substrates covered with poly(methyl methacrylate), and gold (Au) coating on both sides acts as an electrode. The fabricated nanowall nanogenerator produces the maximum output voltage and current of 2.5 V and 80 nA respectively, with maximum power output of 0.2 μW·cm –2, when folding the device through the finger. Furthermore, we studied the performance of the nanogenerator device with different load resistance. The voltage and current were linearly varied with the load resistance. The maximum power output (37.7 nW·cm –2 ) was measured at load resistance of 75 MΩ. The fabricated device showed the capability by driving a commercial green LED and LCD with the help of the capacitor. The experimental results confirmed the ZnO nanowall as a good candidate for energy harvesting application.