scholarly journals Thin Film Gas Sensors Based on Planetary Ball-Milled Zinc Oxide Nanoinks: Effect of Milling Parameters on Sensing Performance

2021 ◽  
Vol 11 (20) ◽  
pp. 9676
Author(s):  
Raju Sapkota ◽  
Pengjun Duan ◽  
Tanay Kumar ◽  
Anusha Venkataraman ◽  
Chris Papadopoulos
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Gas Sensors ◽  
Zno Nanoparticles ◽  
Food Packaging ◽  
Room Temperature ◽  
Industrial Applications ◽  
Sensor Response ◽  
Particle Sizes ◽  
Zno Nanoparticle

Planetary ball-milled zinc oxide (ZnO) nanoparticle suspensions (nanoinks) were used to produce thin film chemiresistive gas sensors that operate at room temperature. By varying milling or grinding parameters (speed, time, and solvent) different thin film gas sensors with tunable particle sizes and porosity were fabricated and tested with dry air/oxygen against hydrogen, argon, and methane target species, in addition to relative humidity, under ambient light conditions. Grinding speeds of up to 1000 rpm produced particle sizes and RMS thin film roughness below 100 nm, as measured by atomic force and scanning electron microscopy. Raman spectroscopy, photoluminescence, and X-ray analysis confirmed the purity and structure of the resulting ZnO nanoparticles. Gas sensor response at room temperature was found to peak for nanoinks milled at 400 rpm and for 30 min in ethylene glycol and deionized water, which could be correlated to an increased film porosity and enhanced variation in electron concentration resulting from adsorption/desorption of oxygen ions on the surfaces of ZnO nanoparticles. Sensor response and dynamic behavior was found to improve as the temperature was increased, peaking between 100 and 150 °C. This work demonstrates the use of low-cost PBM nanoinks as the active materials for solution-processed thin film gas/humidity sensors for use in environmental, medical, food packaging, laboratory, and industrial applications.

ZINC OXIDE NANOPARTICLES FOR ULTRAVIOLET PHOTODETECTION

2011 ◽  
Vol 20 (01) ◽  
pp. 183-194 ◽  
Author(s):  
SHAYLA SAWYER ◽  
LIQIAO QIN ◽  
CHRISTOPHER SHING
Keyword(s):  
Zinc Oxide ◽  
Gallium Nitride ◽  
Zno Nanoparticles ◽  
Green Emission ◽  
Synthesis Process ◽  
Voltage Response ◽  
Zno Nanoparticle ◽  
Linear Current ◽  
Current Voltage ◽  
Lift Off

Zinc Oxide ( ZnO ) nanoparticles were created by a top-down wet-chemistry synthesis process ( ZnO - A ) and then coated with polyvinyl-alcohol (PVA) ( ZnO - U ). In ZnO - U , strong UV emission was apparent while the parasitic green emission, which normally appears in ZnO suspensions, was suppressed. A standard lift-off process via e-beam lithography was used to fabricate a detector by evaporating Aluminum ( Al ) as ohmic electrodes on the ZnO nanoparticle film. Photoconductivity experiments showed that linear current-voltage response were achieved and the ZnO - U nanoparticles based detector had a ratio of UV photo-generated current more than 5 times better than that of the ZnO - A based detector. In addition, non-linear current-voltage responses were observed when interdigitated finger Gold ( Au ) contacts were deposited on ZnO - U . The UV generated current to dark current ratios were between 4 and 7 orders of magnitude, showing better performance than the photodetector with Al contacts. ZnO - U were also deposited on Gallium Nitride ( GaN ) and Aluminum Gallium Nitride ( AlGaN ) substrates to create spectrally selective photodetectors. The responsivity of detector based on AlGaN is twice that of commercial UV enhanced Silicon photodiodes. These results confirmed that ZnO nanoparticles coating with PVA is a good material for small-signal, visible blind, and wavelength selective UV detection.

scholarly journals A tunable volatile organic compound sensor by using PtOx/GQDs/TiO2 nanocomposite thin films at room temperature under visible-light activation

RSC Advances ◽  
2017 ◽  
Vol 7 (63) ◽  
pp. 39859-39868 ◽  
Author(s):  
Shaofeng Shao ◽  
Yunyun Chen ◽  
Shenbei Huang ◽  
Fan Jiang ◽  
Yunfei Wang ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Visible Light ◽  
Gas Sensors ◽  
Room Temperature ◽  
Light Activation ◽  
Nanocomposite Thin Film ◽  
Nanocomposite Thin Films ◽  
Volatile Organic ◽  
Visible Light Activation

Pt/GQDs/TiO2 nanocomposite thin film-based gas sensors show tunable VOC sensing behaviour at room temperature under visible-light activation.

scholarly journals Nonisothermal Kinetic Analysis and AC Conductivity for Polyvinyl Chloride (PVC)/Zinc Oxide (ZnO) Nanocomposite

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Huda AlFannakh
Keyword(s):  
Thermal Stability ◽  
Zinc Oxide ◽  
Kinetic Analysis ◽  
Zno Nanoparticles ◽  
Ac Conductivity ◽  
Zno Nanoparticle ◽  
Nonisothermal Kinetic ◽  
Increasing Temperature ◽  
Host Polymer ◽  
Nonisothermal Kinetic Analysis

The behavior of polyvinyl chlorine (PVC)/zinc oxide (ZnO) nanoparticles was investigated. To improve the dispersion and distribution of zinc nanoparticles within the host polymer (PVC), they were treated with water before being added to the polymer. The nanocomposite samples were prepared by casting method using different weight ratios of ZnO nanoparticles. The prepared nanocomposite samples were characterized by thermogravimetric analysis (TGA). Both thermal stability and kinetic analysis of the prepared samples were investigated. The ZnO nanoparticles lower the activation energy and decrease the thermal stability of PVC. Kissinger, Flynn-Wall-Ozawa, and Kissinger-Akahira-Sunose models were used in the nonisothermal kinetic analysis of PVC/ZnO nanocomposite samples. The thermal stability behavior due to the addition of zinc oxide nanoparticles was explained and correlated with the behavior of the kinetic parameters of the samples. The AC conductivity as function of frequency and temperature was also investigated. The addition of ZnO nanoparticle increases the AC conductivity, and the temperature-independent region decreased by increasing temperature. Both S and A coefficients were predicted using the Jonscher power law and OriginLab software. The trends of S and A coefficients were discussed based on the glass transition of the host polymer.

scholarly journals Antibacterial Activity and Mechanism of Action of Zinc Oxide Nanoparticles againstCampylobacter jejuni

2011 ◽  
Vol 77 (7) ◽  
pp. 2325-2331 ◽  
Author(s):  
Yanping Xie ◽  
Yiping He ◽  
Peter L. Irwin ◽  
Tony Jin ◽  
Xianming Shi
Keyword(s):  
Oxidative Stress ◽  
Zinc Oxide ◽  
Stress Response ◽  
Quantitative Pcr ◽  
Zno Nanoparticles ◽  
Morphological Changes ◽  
Toxin Production ◽  
Response To Treatment ◽  
Large Set ◽  
Zno Nanoparticle

ABSTRACTThe antibacterial effect of zinc oxide (ZnO) nanoparticles onCampylobacter jejuniwas investigated for inhibition and inactivation of cell growth. The results showed thatC. jejuniwas extremely sensitive to treatment with ZnO nanoparticles. The MIC of ZnO nanoparticles forC. jejuniwas determined to be 0.05 to 0.025 mg/ml, which is 8- to 16-fold lower than that forSalmonella entericaserovar Enteritidis andEscherichia coliO157:H7 (0.4 mg/ml). The action of ZnO nanoparticles againstC. jejuniwas determined to be bactericidal, not bacteriostatic. Scanning electron microscopy examination revealed that the majority of the cells transformed from spiral shapes into coccoid forms after exposure to 0.5 mg/ml of ZnO nanoparticles for 16 h, which is consistent with the morphological changes ofC. jejuniunder other stress conditions. These coccoid cells were found by ethidium monoazide-quantitative PCR (EMA-qPCR) to have a certain level of membrane leakage. To address the molecular basis of ZnO nanoparticle action, a large set of genes involved in cell stress response, motility, pathogenesis, and toxin production were selected for a gene expression study. Reverse transcription-quantitative PCR (RT-qPCR) showed that in response to treatment with ZnO nanoparticles, the expression levels of two oxidative stress genes (katAandahpC) and a general stress response gene (dnaK) were increased 52-, 7-, and 17-fold, respectively. These results suggest that the antibacterial mechanism of ZnO nanoparticles is most likely due to disruption of the cell membrane and oxidative stress inCampylobacter.

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