• 센서학회지
• /
• 제31권2호
• /
• pp.125-130
• /
• 2022

We describe the importance of zinc oxide nanoparticle (ZnO NP) concentration in the enhancement of electrical properties in a lead sulfide quantum dot (PbS QD)-based shortwave infrared (SWIR) photodetector. ZnO NPs were synthesized using the sol-gel method. The concentration of the ZnO NPs was controlled as 20, 30 and 40 mg/mL in this study. Note that the ZnO NPs layer is commonly used as an electron transport layer in PbS QDs SWIR photodetectors. The photo-to-dark ratio, which is an important parameter of a photodetector, was intensively examined to evaluate the electrical performance. The 20 mg/mL condition of ZnO NPs exhibited the highest photo-to-dark ratio value of 5 at -1 V, compared with 1.8 and 0.4 for 30 mg/mL and 40 mg/mL, respectively. This resulted because the electron mobility decreased when the concentration of ZnO NPs was higher than the optimized value. Based on our results, the concentration of ZnO NPs was observed to play an important role in the electrical performance of the PbS QDs SWIR photodetector.

• Advances in Energy Research
• /
• 제4권4호
• /
• pp.275-284
• /
• 2016

In the present work, ZnO nanoparticles (NPs) have been dispersed alone in the same solvent of the active layer for improving performance parameters of the organic solar cells. Different concentrations of the ZnO NPs have been blended inside active layer of the solar cell based on poly(3-hexylthiophene) (P3HT), which forms the hole-transport network, and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), which forms the electron-transport network. In the present investigations, the ZnO NPs may represent an efficient tool for improving light harvesting through light scattering inside active layer, electron mobility, and electron acceptance strength which tend to improve photocurrent and performance parameters of the investigated solar cell. The fill factor (FF) of the ZnO-doped solar cell increases nearly 14% compared to the non-doped solar cell when the doping is 50%. The present investigations show that ZnO NPs improve power conversion efficiency of the solar cell from 1.23% to 1.64% with increment around 25% that takes place after incorporation of 40% as a volume ratio of the ZnO NPs inside P3HT:PCBM active layer.

• The Plant Pathology Journal
• /
• 제39권3호
• /
• pp.265-274
• /
• 2023

Citrus black rot is a serious disease of citrus plants caused by Alternaria citri. The current study aimed to synthesize zinc oxide nanoparticles (ZnO-NPs) by chemically or green method and investigate their antifungal activity against A. citri. The sizes of synthesized as measured by transmission electron microscope of ZnO-NPs were 88 and 65 nm for chemical and green methods, respectively. The studied prepared ZnO-NPs were applied, in vitro and in situ, at different concentrations (500, 1,000, and 2,000 ㎍/ml) in post-harvest treatment on navel orange fruits to verify the possible control effect against A. citri. Results of in vitro assay demonstrated that, at concentration 2,000 ㎍/ml, the green ZnO-NPs was able to inhibit about 61% of the fungal growth followed by 52% of chemical ZnO-NPs. In addition, scanning electron microscopy of A. citri treated in vitro with green ZnO-NPs showed swelling and deformation of conidia. Results showed also that, using a chemically and green ZnO-NPs at 2,000 ㎍/ml in situ in post-harvest treatment of orange, artificially-infected with A. citri, has reduced the disease severity to 6.92% and 9.23%, respectively, compared to 23.84% of positive control (non-treated fruits) after 20 days of storage. The out findings of this study may contribute to the development of a natural, effective, and eco-friendly strategy for eradicating harmful phytopathogenic fungi.

• 청정기술
• /
• 제27권4호
• /
• pp.291-296
• /
• 2021

물에 잔존하는 유기오염물질이 인체 및 환경에 미치는 악영향을 해결하기 위한 방법으로 오염물질을 친환경적으로 분해할 수 있는 광촉매 기술이 대두되고 있다. 대표적인 광촉매 물질로 TiO₂ 입자가 사용되고 있지만 비싼 가격으로 인해 이를 대체하고자 하는 노력이 지속적으로 수행되었다. 본 연구에서는 이러한 노력의 일환으로 미세유체공정을 사용하여 보다 가격경쟁력이 우수한 ZnO입자를 합성하였다. ZnO의 넓은 밴드갭으로 인해 촉매활성이 제한되는 단점을 해결하고자 동일 공정을 사용하여 은(Ag) 나노입자를 ZnO 표면에 증착하여 Ag-ZnO 나노복합체를 생산하였다. 다양한 분석법을 사용하여 나노복합체의 형상, 구조, 및 성분 분석을 진행한 결과 고품질의 Ag-ZnO 나노복합체가 합성됨을 확인했으며, 메틸렌블루 분해 실험을 통해서 광촉매 활성을 측정하였다. Ag-ZnO 나노복합체의 플라스몬 효과와 광반응에 의해 생성된 전자와 정공의 분리 효과에 의해 광촉매 활성 효율이 순수한 ZnO 입자와 비교하여 향상되었음을 확인하였다. Microreactor-assisted nanomaterials (MAN) 공정 기반의 나노복합체는 가격경쟁력이 우수하고 공정이 용이하다는 장점이 있기에 나노복합체 광촉매를 대량 생산하기 위한 잠재력이 우수하다고 사료된다.

• 대한환경공학회지
• /
• 제31권7호
• /
• pp.467-472
• /
• 2009

Seedling 성장 실험은 나노입자에 대한 독성 평가로 사용되어 왔다. 본 연구에서는 오이에 대한 나노 아연과 나노 산화아연의 독성을 filter paper방법과 phytagel방법을 통해 평가해 보았다. 비교 결과 phytagel방법이 불용성인 나노아연, 산화 아연의 침전을 방지했다. 오이 seedling 길이는 노출된 나노 아연, 나노 산화 아연의 농도에 따라 filter 방법에서 음의 관계를 나타냈다. 나노 아연과 나노 산화 아연에 대한 오이의 EC50값은 598, 600 mg/L로 나타났다. Filter paper방법에서만 아연의 오이 내 생체 축적량은 노출된 나노 아연, 나노 산화 아연의 농도에 따라 증가하였다. 관찰 결과 filter paper방법이 phytagel 방법보다 더 좋은 protocol로 나타났다

• Membrane and Water Treatment
• /
• 제6권4호
• /
• pp.309-321
• /
• 2015

We report in this study the synthesis of mixed matrix reverse osmosis membranes by interfacial polymerization (IP) of thin film nanocomposite (TFNC) on porous polysulfone supports (PS). This paper investigates the synthesis of ZnO nanoparticles (NPs) using the sol-gel processing technique and evaluates the performance of mixed matrix membranes reached by these aerogel NPs. Aqueous m-phenyl diamine (MPD) and organic trimesoyl chloride (TMC)-NPs mixture solutions were used in the IP process. The reaction of MPD and TMC at the interface of PS substrates resulted in the formation of the thin film composite (TFC). NPs of ZnO with a size of about 25 nm were used for the fabrication of the TFNC membranes. These membranes were characterized and evaluated in comparison with neat TFC ones. Their performances were evaluated based on the water permeability and salt rejection. Experimental results indicated that the NPs improved membrane performance under optimal concentration of NPs. By changing the content of the filler, better hydrophilicity was obtained; the contact angle was decreased from $74^{\circ}$ to $32^{\circ}$. Also, the permeate water flux was increased from 26 to 49 L/m2.h when the content of NPs is 0.1 (wt.%) with the maintaining of lower salt passage of 1%.

• 한국자원식물학회:학술대회논문집
• /
• 한국자원식물학회 2018년도 춘계학술발표회
• /
• pp.93-93
• /
• 2018

This study disclosed the aqueous fruits extract of Rubus coreanus as a sustainable agent for the synthesis of Rubus coreanus zinc oxide nanoparticle (Rc-ZnO Nps) using as a reducing and capping precursor for co-precipitation method. The development of Rc-ZnO was assured by white precipitated powder and analyzed by spectroscopic and analytical instruments. The UV-visible (UV-Vis) studies indicate the maximum absorbance at 357nm which confirmed the formation of ZnO Nps and the purity, functional group and monodispersity were assured by field emission transmission electron microscopy (FE-TEM), Fourier Transform Infrared (FTIR) Spectroscopy and dynamic light scattering (DLS). The X-ray powder diffraction (XRD) data revealed the Nps is 23.16 nm in size, crystalline in nature and possess hexagonal wurtzite structure. The Rc-ZnO Nps were subjected for catalytic studies. The Malachite Green dye was degraded by Rc- ZnO NPs in both dark and light (100 W tungsten) conditions and it degraded about 90% at 4 hours observation in both cases. The biodegradable, low cost Rc-ZnO NPs can be a better weapon for waste water treatment.

• Advances in nano research
• /
• 제7권4호
• /
• pp.233-240
• /
• 2019

The present research work reports in-vitro anti-cancer activity of biologically synthesized ZnO nanoparticles (ZnO NPs) against human carcinoma cells viz SCC-40, SK-MEL-2 and SCC-29B using Sulforhodamine-B (SRB) Assay. ZnO NPs were synthesized by a unique and novel biological route using Temperature-gradient phenomenon where the extract of combination of Catharanthus roseus (L.) G. Don (C. roseus), Azadirachta indica (A. indica), Ficus religiosa (F. religiosa) and NaOH solution were used as synthesis medium. The morphology of the ZnO NPs was characterized by Transmission Electron Microscopy (TEM). TEM images reveal that particle size of the samples reduces from 76 nm to 53 nm with the increase in reaction temperature and 68 nm to 38 nm with the increase in molar concentration of NaOH respectively. XRD study confirms the presence of elements and reduction in crystallite size with increase in reaction temperature and NaOH concentration. The diffraction peaks show broadening and a slight shift towards lower Bragg angle ($2{\theta}$) which represents the reduction in crystallite size as well as presence of uniform strain. The FTIR spectra of the extract show transmittance peak fingerprint of Zn-O bond and presence of bioactive molecules These NPs exhibit inhibition greater than 50% for SCC-40, SK-MEL-2 and SCC-29B cell lines and more than 50% cell kill for SCC-29B cells at concentrations < $80{\mu}g/ml$. Nanoparticles with smallest size have shown better anti-cancer activity and peculiar cell-selectivity. The combination of extracts of these plants with ZnO NPs can be used in targeted drug delivery as an effective anti-cancer agent, a potential application in cancer treatment.

• Journal of Microbiology and Biotechnology
• /
• 제23권9호
• /
• pp.1279-1286
• /
• 2013

Particle size and metal species are important to both soil microbial toxicity and phytotoxicity in the soil ecosystem. The effects of CuO and ZnO nanoparticles (NPs) and microparticles (MPs) on soil microbial toxicity, phytotoxicity, and bioaccumulation in two crops (Cucumis sativus and Zea mays) were estimated in a soil microcosm. In the microcosm system, soil was artificially contaminated with 1,000 mg/kg CuO and ZnO NPs and MPs. After 15 days, we compared the microbial toxicity and phytotoxicity by particle size. In addition, C. sativus and Z. mays were cultivated in soils treated with CuO NPs and ZnO NPs, after which the treatment effects on bioaccumulation were evaluated. NPs were more toxic than MPs to microbes and plants in the soil ecosystem. We found that the soil enzyme activity and plant biomass were inhibited to the greatest extent by CuO NPs. However, in a Biolog test, substrate utilization patterns were more dependent upon metal type than particle size. Another finding indicated that the metal NP uptake amounts of plants depend on the plant species. In the comparison between C. sativus and Z. mays, the accumulation of Cu and Zn by C. sativus was noticeably higher. These findings show that metal oxide NPs may negatively impact soil bacteria and plants. In addition, the accumulation patterns of NPs depend on the plant species.

• Environmental Engineering Research
• /
• 제22권2호
• /
• pp.224-229
• /
• 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.