The piezoelectric potential output has been studied using a ZnO nanorods (NRs) grown atomic force microscope (AFM) tip in lieu of the normally used AFM tip. The ZnO NRs were synthesised on the AFM tip and on the fluorine-doped tin oxide (FTO) glass substrate using the aqueous chemical growth method. The as-grown ZnO NRs were highly dense, well aligned and uniform both on the tip and on the substrate. The structural study was performed using X-ray diffraction and scanning electron microscopy techniques. The piezoelectric properties of as-grown ZnO NRs were investigated using an AFM in contact mode. In comparison to the AFM tip without ZnO NRs, extra positive voltage peaks were observed when the AFM tip with ZnO NRs was used. The pair of ZnO NRs on the AFM tip and on the FTO glass substrate together worked as two oppositely gliding walls (composed of ZnO NRs) and showed an enhancement in the amount of the harvested energy as much as eight times. This approach demonstrates that the use of the AFM tip with ZnO NRs is not only a good alternative to improve the design of nanogenerators to obtain an enhanced amount of harvested energy but is also simple, reliable and cost-effective.
Nanostructure ZnO was grown on thin aluminium layer, deposited on silicon substrate using the sol-gel method. The surface morphologies of nanostructure ZnO at different precursor concentrations were studied using scanning electron microscopy. Raman spectroscopy suggested that nanorods started to grow along with nanoflakes at a precursor concentration of 50 mM and the density of the nanorods significantly increases when the concentration was raised to 75 mM. Raman spectra were intensified and red shifted with the increment of precursor concentration. Optical properties of refractive index and optical dielectric constant are investigated. The structural defects at lower level of precursor were probably due to the hypoxic environment, whereas the red shift of Raman spectra was due to the structural change of ZnO nanocrystals.
In the present study, highly oriented single-crystal zinc oxide nanotube (ZnO-NT) arrays were prepared by a trimming of ZnO nanorods along the c-axis on the gold-coated glass substrate having a diameter of 100-200 nm and a length of similar to 1 mu m using a low-temperature aqueous chemical growth process. The prepared (ZnO-NT) arrays were further used as electrochemical enzyme-based glucose sensors through immobilisation of glucose oxidase by the physical adsorption method in conjunction with a Nafion coating. The electrochemical response of the sensor was found to be linear over a relatively wide logarithmic concentration range from 0.5 x 10(-6) to 12 x 10(-3) M. The proposed sensor showed a high sensitivity of 69.12 mV/decade with R = 0.9934 for sensing of glucose. A fast-response time less than 4 s with good selectivity, reproducibility and negligible response to common interferents such as ascorbic acid and uric acid prevailed.