• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.235.2-235.2
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• 2015

The front transparent conductive oxide (TCO) films must exhibit good transparency, low resistivity and excellent light scattering properties for high efficiency amorphous silicon (a-Si) thin film solar cells. The light trapping phenomenon is limited due to non-uniform and low aspect ratio of the textured glass [1]. We present the low cost electrochemically deposited uniform zinc oxide (ZnO) nanorods with various aspect ratios for a-Si thin film solar cells. Since the major drawback of the electrochemically deposited ZnO nanorods was the high sheet resistance and low transmittance that was overcome by depositing the RF magnetron sputtered AZO films as a seed layer with various thicknesses [2]. The length and diameters of the ZnO nanorods was controlled by varying the deposition conditions. The length of ZnO nanorods were varied from 400 nm to $2{\mu}m$ while diameter was kept higher than 200 nm to obtain different aspect ratios. The uniform ZnO nanorods showed higher haze ratio as compared to the commercially available FTO films. We also observed that the scattering in the longer wavelength region was favored for the high aspect ratio of ZnO nanorods and much higher aspect ratios degraded the light scattering phenomenon. Therefore, we proposed our low cost and uniform ZnO nanorods for the high efficiency of thin film solar cells.

• Applied Chemistry for Engineering
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• v.21 no.2
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• pp.224-229
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• 2010

Transparent conductive oxide films have been widely used in the field of flat panel display (FPD). Transparent conductive Indium Zinc Oxide (IZO) thin films with excellent chemical stability have attracted much attention as an alternative material for Indium Tin Oxide (ITO) films. In this study, using $In_2O_3$ and ZnO powder mixture with a ratio of 90 : 10 wt% as a target, IZO films are prepared on polynorbornene (PNB) substrates by electron beam evaporation. The effect of thickness and $O_2$ introduction flow rate on the optical, electrical, structural properties and surface composition of deposited IZO films were investigated by UV/Visible spectrophotometer, 4-point probe method, SEM, XRD and XPS.

• The Korean Journal of Ceramics
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• v.3 no.4
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• pp.269-273
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• 1997

Chemical composition of cement powder influences the setting time and early compressive strength development. The setting time increases as the amounts of zinc oxide and magnesium oxide are increased. For one day compressive strength development, a cement powder with a composition 90% ZnO, 8% MgO and 2% silica resulted in the highest strength (greater than 1, 090 kg/$\textrm{cm}^2$). Cement-forming liquids also need to be buffered, with both aluminum and zinc ions, for a good consistency and a higher strength of the zinc phosphate cement. These liquids control the setting reactions.

• Korean Journal of Materials Research
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• v.25 no.7
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• pp.358-363
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• 2015

We present an excellent detection for nitrogen monoxide (NO) gas using polycrystalline ZnO wire-like films synthesized via a simple method combined with sputtering of Zn metallic films and subsequent thermal oxidation of the sputtered Zn nanowire films in dry air. Structural and morphological characterization revealed that it would be possible to synthesize polycrystalline hexagonal wurtzite ZnO films of a wire-like nanostructure with widths of 100-150 nm and lengths of several microns by controlling the sputtering conditions. It was found from the gas sensing measurements that the ZnO wire-like thin film gas sensor showed a significantly high response, with a maximum value of 29.2 for 2 ppm NO at $200^{\circ}C$, as well as a reversible fast response to NO with a very low detection limit of 50 ppb. In addition, the ZnO wire-like thin film gas sensor also displayed an NO-selective sensing response for NO, $O_2$, $H_2$, $NH_3$, and CO gases. Our results illustrate that polycrystalline ZnO wire-like thin films are potential sensing materials for the fabrication of NO-sensitive high-performance gas sensors.

• Journal of the Korean institute of surface engineering
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• v.51 no.4
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• pp.237-242
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• 2018

We report on the fabrication and photoelectrochemical (PEC) properties of a ZnO nanorod array structure as an efficient photoelectrode for hydrogen production from sunlight-driven water splitting. Vertically aligned ZnO nanorods were grown on an indium-tin-oxide-coated glass substrate via seed-mediated hydrothermal synthesis method with the use of a ZnO nanoparticle seed layer, which was formed by thermally oxidizing a sputtered Zn metal thin film. The structural and morphological properties of the synthesized ZnO nanorods were examined using X-ray diffraction and scanning electron microscopy, as well as Raman scattering. The PEC properties of the fabricated ZnO nanorod photoelectrode were evaluated by photocurrent conversion efficiency measurements under white light illumination. From the observed PEC current density versus voltage (J-V) behavior, the vertically aligned ZnO nanorod photoelectrode was found to exhibit a negligible dark current and high photocurrent density, e.g., $0.65mA/cm^2$ at 0.8 V vs Ag/AgCl in a 1 mM $Na_2SO_4$ electrolyte. In particular, a significant PEC performance was observed even at an applied bias of 0 V vs Ag/AgCl, which made the device self-powered.

• Structural Monitoring and Maintenance
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• v.4 no.2
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• pp.107-113
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• 2017

In this paper, we present a strain-sensitive composite skin-like film made up of piezoresistive zinc oxide (ZnO) nanorods embedded in a flexible poly(dimethylsiloxane) substrate, with added reduced graphene oxide (rGO) to facilitate connections between the nanorod clusters and increase strain sensitivity. Preparation of the composite is described in detail. Cyclic strain sensing tests are conducted. Experiments indicate that the resulting ZnO-PDMS/rGO composite film is strain-sensitive and thus capable of sensing cycling strain accurately. As such, it has the potential to be molded on to a structure (civil, mechanical, aerospace, or biological) in order to provide a strain sensing skin.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.703-706
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• 2006

Zinc oxide nanocrystals are attractive candidates for a solution-processable semiconductor for high performance thin film field effect transistors. We have studied ZnO thin film transistor fabricated by solution process and have improved $V_{th}$ by controlling the ZnO ink additives. Synthesized ZnO nanoparticles of 30nm were dispersed in solvent to make the ZnO ink. ZnO ink was spin coated on silicon wafer and after heat treatment electrodes were patterned.

• Environmental Engineering Research
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• v.22 no.2
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• pp.224-229
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• 2017

Zinc oxide nanoparticles (ZnO NPs) have been used as additives in a variety of consumer products. While these particles may enter the environment, only a limited number of studies have investigated the effects of ZnO NPs on soil exoenzymes. Here, we investigate the long-term effects of ZnO NPs at concentrations of 50 and 500 mg/kg on the activities of six soil exoenzymes in planted soils: Dehydrogenase, fluorescein diacetate (FDA) hydrolase, urease, acid phosphatase, arylsulfatase, and ${\beta}-glucosidase$. Significant effects were observed at one or more time points for all enzymes except for FDA hydrolase. These effects included both decreases and increases in enzyme activity. Our results suggest that ZnO NP treatments of 50 and 500 mg/kg can adversely affect soil enzymes, particularly acid phosphatase and urease, and thus, these data may have implications for phosphorous and nitrogen cycles in the soil.

• Food Science and Preservation
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• v.31 no.1
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• pp.126-137
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• 2024

In this study, zinc oxide nanoparticles (ZnONPs) were synthesized using three distinct zinc salts: zinc acetate, zinc chloride, and zinc nitrate. These ZnONPs were subsequently utilized in the fabrication of carrageenan-ZnONPs (Car-ZnONPs) composite films. The study assessed influence of the various ZnONPs on the morphological, water vapor barrier, color, optical, and antimicrobial properties of the Car-ZnONPs composite films. The surface morphology and UV-blocking attributes of the composite films were affected by the type of ZnONPs used, but their surface color, transparency, and chemical structure remained unaltered. The composite film's thickness and elongation at break (EB) significantly increased, while the tensile strength significantly decreased. In contrast, film's elastic modulus (EM) and water vapor permeability coefficient (WVP) showed no significant difference. All the composite films with added ZnONPs demonstrated potent antibacterial activity against Escherichia coli O157:H7 and Listeria monocytogenes . Among the carrageenan-based composite films, Car-ZnONPs^ZC showed the highest antibacterial and UV-blocking properties, and its elongation at break was significantly higher than that of the pure carrageenan films. This suggests that ZnONPs composite films have the potential to be used as an active packaging film, preserve the safety of the packaged food and extend shelf life.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.7
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• pp.467-472
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• 2009

Seedling growth test is used to assess toxicity of nanoparticles (NPs). This study evaluates toxicity of zinc, zinc oxide NPs on Cucumis sativus using two methods; phytagel and filter paper. From the comparison, phytagel method prevents precipitation of water insoluble NPS. Seeding length was negatively related to the exposed concentration of Zn, ZnO NPs in filter method. The median effective concentrations (EC50) for C. sativus exposed to Zn, ZnO NPs were estimated about 598, 600 mg/L in filter method. Bioaccumulation increased with the exposed concentration of Zn, ZnO NPs in only filter method. The results showed that the filter paper method was much better protocol than phytagel method.