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High-quality vertically aligned zinc oxide (ZnO) nanorods were successfully grown on seeded silicon substrates p-Si(100) through microwave-assisted chemical bath deposition. Structural and morphological analyses revealed hexagonal wurtzite nanorods perpendicular to the substrate along the c-axis in the direction of the (002) plane. Optical measurements showed a high-intensity UV peak with a low broad visible peak. UV emission was compared with the visible emission having an IUV/Ivis ratio of 53. A metal-semiconductor-metalbased UV detector was then fabricated by depositing two metal contacts onto the ZnO nanorod surfaces. Current-voltage measurements revealed a highly sensitive device with a self-powered characteristic. At zero applied bias, the fabricated device showed a significant difference between the UV current and dark current. The device further showed a sensitivity of 304 × 104 to low-power (1.5 mW/cm2) 365 nm light pulses without an external bias. Photoresponse measurements demonstrated the highly reproducible characteristics of the fabricated UV detector with rapid response and baseline recovery times of 10 ms. This work introduced a simple, low-cost method of fabricating rapid-response, highly photosensitive UV detectors with zero power consumption.

AbstractThe preparation of conductive polypyrrole (PPy) nanocomposite with cellulose nanocrystals (CNC) was carried out by situ polymerization method. The new water dispersible sample (PPy-CNC) was deposited as a thin film on the paper sheet substrate as a conductive paper. The images of field emission scanning electron microscopy (FESEM) clearly shw the morphological modulation and the uniformity of the PPy-CNC sample. The electrical properties of conductive paper were studied with various acid doping values. The results show increase in the electrical properties along with the decrease of pH value. Cyclic voltammetry (CV) test was used to examine the stability of redox properties of the neat sample before the doping process. The mechanical properties such as tensile index and elongation at break shows slight decline with decreasing pH. However, elongation at break results for 0.65 pH sample shows different respond to pH value.

Conductive polyaniline (PANI) in various nanostructures were prepared by situ polymerization for corrosion protection application of carbon steel. Anticorrosion performance of the samples was evaluated by applying salt spray and adhesion tests based on standards ASTM B117 and ASTM D3359 respectively. Synthesis of PANI in various nanostructures carried out by doping aniline monomer with phosphoric acid in four different molar ratios. Field emission scanning electron microscopy (FESEM) images confirms the variation in nanostructures of samples. The samples were also characterized using Fourier transform infrared (FTIR), X-ray diffraction (XRD), electrical conductivity and dispersion stability in ethanol medium. The transition of PANI nanostructure from nanofibers to nanorods and nanospheres occurred with the increase of molar ratios (phosphoric acid/aniline) from 0.1, 0.5, 1 and 2 respectively. The results show that coating containing PANI nanofibers has the best resistance against corrosive aggression due to the high dispersion stability and decent uniformity. Accordingly, this work finds that the morphological structure and dispersion stability for PANI has a significant impact on the anticorrosion performance.