ZnO Hexagonal Nanodisks Research Articles

Evolution of ZnO nanostructures as hexagonal disk: Implementation as photoanode material and efficiency enhancement in Al: ZnO based dye sensitized solar cells

Hexagon shaped pristine and Al doped ZnO nanodisks (NDs) with exposed ±[0001] polar facets were successfully synthesized using modified sol-gel method without the involvement of any structural directing or capping agents. It was investigated that OH− ions in mixed solvent system is responsible for pore formation and inhibit the growth of ZnO along the direction of c-axis leading to a high percentage exposure of active ±[0001] polar facets and encourage the formation of ZnO NDs. Crystallographic analysis revealed that crystallite size and lattice constants are decreased, with the addition of Al3+ ions. The results obtained from Raman, and XPS analysis further corroborated with the XRD results, revealed the successful incorporation of Al3+ ions into ZnO lattice. Optical study revealed the band gap tunability with the incorporation of Al ion as dopant. Enhanced power conversion efficiency (PCE) of 1.96% (Jsc ∼ 7.69 ± 0.23 mA/cm2) was observed for Al: ZnO hexagonal NDs based DSSC. The increased PCE in Al: ZnO based DSSC can be attributed to the higher inner surface area for dye anchoring by the interconnected network of the disk-like structure. The obtained results were satisfactory and most importantly the synthesis procedure proposed in present work is excellent for the synthesis of perfectly hexagonal shaped disks under précised synthesis parameters. The device interface study was further conducted using electrochemical impedance spectroscopy which revealed better charge transport process and charge storage ability with the incorporation of Al3+ ions into ZnO lattice.

Synthesis of Hexagonal ZnO-PQ7 Nano Disks Conjugated with Folic Acid to Image MCF - 7 Cancer Cells.

Surface modified ZnO nanomaterial is widely used in the field of bioimaging worldwide due to its optical properties, electronic characteristics and biocompatibility. Fluorescent enhanced, Polyquaternium-7(PQ7) capped, ZnO hexagonal nano disks (ZnO-PQ7) were synthesised by simple wet chemical method. The structural and optical properties of ZnO-PQ7 hexagonal nano disks were characterized using XRD, UV-Visible, Fluorescence, HRTEM, EDAX and FTIR studies. The size of synthesised ZnO-PQ7 were around 30-45nm asconfirmed by HRTEM studies. Fluorescence emission intensity increased with increase in PQ7 concentration. ZnO-PQ7 was further conjugated with folic acid (FA) to target human breast cancer cell line (MCF-7) via EDC/NHS coupling chemistry. Conjugation of folic acid with ZnO-PQ7 was confirmed by FTIR studies. The cell viability study using Methyl thiazolyltetrazolium(MTT) assay has demonstrated that the ZnO-PQ7 conjugated FA composites (ZnO-PQ7-FA) exhibit low toxicity towards MCF-7 up to a concentration of 125μg/mL. Confocal laser scanning microscopic images confirmed the uptake of ZnO-PQ7-FA nanoparticles by MCF-7 cells. This study reveals ZnO-PQ7-FA nano disks as a potential imaging agent for detection of cancer cells. The synthesis route reported in this article is simple and easy to follow for the synthesis of ZnO-PQ7-FA in bulk quantities with high purity.

CeO2[sbnd]ZnO hexagonal nanodisks: Efficient material for the degradation of direct blue 15 dye and its simulated dye bath effluent under solar light

Well-crystalline CeO2ZnO hexagonal nanodisks were synthesized by simple and facile chemical reaction process at low-temperature and characterized in detail by using several techniques such as powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA), UV–vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) emission spectroscopy and X-ray photoelectron spectroscopy (XPS). The detailed characterizations results revealed that the prepared samples are well-crystalline with good optical and structural properties and possessing hexagonal morphologies. Further, the prepared material was used as efficient photocatalyst for the photocatalytic degradation of highly hazardous direct blue (DB)-15 dye under solar light irradiation. The CeO2ZnO hexagonal nanodisks exhibited superior photocatalytic performance towards the degradation of DB 15 dye and its simulated dye bath effluent under solar light. The enhanced photocatalytic activity of CeO2ZnO hexagonal nanodisks could be attributed to the suppression of photo-induced e−/h+ pair recombination. Moreover, various scavengers have been used to study the role of reactive species in the photo-degradation process.

Structural, Electronic and Infrared Spectral Properties of ZnO Hexagonal Nanodisks with Different Saturate Conditions

Structural, Electronic and Infrared Spectral Properties of ZnO Hexagonal Nanodisks with Different Saturate Conditions

Frequency-upconverted whispering-gallery-mode lasing in ZnO hexagonal nanodisks

Low threshold, frequency-upconverted lasing in the two-photon absorption regime was observed in hexagonal ZnO nanodisks. Upon near-IR excitation, the ZnO nanodisk resonators produced UV laser emission with a remarkably low threshold (approximately 1 mJ/cm(2)) as well as a resolved lasing linewidth of approximately 0.1 nm. Modal analysis and far-field photoluminescence imaging of the nanolasers have suggested the dominance of whispering-gallery modes in the two-photon pumped microcavity lasing process.