Ag-coated cotton fabric as ultrasensitive and flexible SERS substrate

2021 ◽  
pp. 152808372110277
Author(s):  
Xueyan Bian ◽  
Jiangtao Xu ◽  
Yi Pu ◽  
Jing Yang ◽  
Ka-lam Chiu ◽  
...  
Keyword(s):  
Cotton Fabric ◽  
Flow Rate ◽  
Ag Nanoparticles ◽  
Fdtd Method ◽  
Raman Signal ◽  
Enhancement Effect ◽  
Sers Substrate ◽  
Argon Flow Rate ◽  
Practical Applications ◽  
Argon Flow

Surface enhanced Raman scattering (SERS) has proven to be increasingly valuable as an analytical tool since this phenomenon was first observed in 1973. However, challenges still exist to ensure their ability to access targeted analytes and adequate levels of sensitivity to them on irregular surfaces. Herein, silver (Ag) nanoparticles are deposited onto cotton fabric through magnetron sputtering to develop a flexible and ultrasensitive SERS-active substrate. To obtain a better enhancement effect, Ag nanoparticles of different sizes are produced by controlling the argon flow rate and the sputtering time. The finite-difference time-domain (FDTD) method and Raman mapping are used to explain the process behind Raman signal enhancement. The cotton fabric sample with Ag nanoparticles deposited at an argon flow rate of 200  sccm (labelled as AC-200) shows a high enhancement factor (EF) of 104 with a Methylene blue (MB) solution of 10−3 M, stability with a related standard deviation (RSD) of 1.03%, excellent reproducibility with an RSD of 1.92% and high sensitivity with 10−9 M of MB solution. Therefore, AC-200 demonstrates exceptional SERS signal reproducibility and stability for different types of chemical analytes and has the potential to be used in future practical applications.

Nano Cuprous Oxides Film Prepared by Magnetron Sputtering

2004 ◽  
Vol 822 ◽  
Author(s):  
Yang-Ming Lu ◽  
Jun-Yuan Chen ◽  
Tzuu-Shaang Wey
Keyword(s):  
Substrate Temperature ◽  
Flow Rate ◽  
Cuprous Oxide ◽  
Rate Ratio ◽  
Single Phase ◽  
Flow Rate Ratio ◽  
Argon Flow Rate ◽  
Practical Applications ◽  
Argon Flow ◽  
Pure Cu

AbstractCuprous oxide (Cu2O) is a direct-gap semiconductor with band-gap energy of 2.0 eV and has been extensively investigated as a candidate for a photovoltaic material. However, practical applications have not been achieved to date due to the difficulty in controlling its physical properties. We have investigated the controllability of the formation of pure Cu2O thin films deposited by the reactive DC sputtering method and analysis by XPS and Raman spectrometer to identify the Cu+1 in the cuprous oxide. The formation of pure Cu2O films is not only dependent on the substrate temperature but also strongly effected by the oxygen and argon flow rate ratio. When the substrate temperature was kept constant at 100°C and varied the oxygen and argon flow rate ratio from 3ml/min to 10ml/min, it is found a mixture of Cu2O and CuO phases is formed. At the flow rate of oxygen to 5ml/min, the pure and single phase of Cu2O is formed. Further increasing the oxygen flow rate, the phase is changed to be the CuO phase. The crystallity is improved as increasing the substrate temperature. The electrical resistivity of Cu2O obtained in this study is about 316 ohm-cm at 100°C substrate temperature and 2.66Pa condition. The dependence of cupper oxides resistivity is not only on the substrate temperature and reactive gases but also on the sputter pressure. Because the characteristic resistivity values change with sputter pressure variation due to different phase compositions forming in the films. The lowest resistivity of Cu2O film is obtained when the Cu2O single phase exists in the films.

PHOTO-CATALYTIC ACTIVITY AND PHOTO-ABSORPTION OF PLASMA-SPRAYED NANO-STRUCTURED TiO2 COATINGS

2010 ◽  
Vol 24 (31) ◽  
pp. 6115-6127 ◽  
Author(s):  
MARYAMOSSADAT BOZORGTABAR ◽  
MEHDI SALEHI ◽  
MOHAMMADREZA RAHIMIPOUR ◽  
MOHAMMADREZA JAFARPOUR
Keyword(s):  
Catalytic Activity ◽  
Flow Rate ◽  
Test Chamber ◽  
Catalytic Efficiency ◽  
Surface Characteristics ◽  
Catalytic Performance ◽  
Atmospheric Plasma ◽  
Argon Flow Rate ◽  
Photo Catalytic Activity ◽  
Argon Flow

Titanium dioxide coatings were deposited by utilizing atmospheric plasma-spraying system. The agglomerated P25/20 nano-powder and different spraying parameters (e.g., Argon flow rate and spray distance) were used to determine their influences on the microstructure, crystalline structure, photo-absorption, and photo-catalytic performance of the coatings. The microstructure and phases of as-sprayed TiO 2 coatings were characterized by scanning electron microscope SEM and X-ray diffraction, respectively. Surface characteristics were investigated by Fourier Transform Infrared. Photo-catalytic efficiency of the elaborated samples was also determined in an environmental test chamber set-up and evaluated from the conversion rate of ethanol. The photo-absorption was determined by UV–Vis spectrophotometer. The as-sprayed TiO2 coating was photo-catalytically reactive for the degradation of ethanol. The photo-catalytic activity was influenced by spray conditions. It is found that the photo-catalytic activity is significantly influenced by anatase content, surface area, and surface state. The results showed that the argon flow rate has an influence on the microstructure, anatase content, and photo-catalytic activity of the TiO 2 coatings.

scholarly journals Organic Molecule Detection Based on SERS in Microfluidics

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xin Zhang ◽  
Haiyan Zhang ◽  
Sheng Yan ◽  
Zugang Zeng ◽  
Anshou Huang ◽  
...  
Keyword(s):  
Environmental Monitoring ◽  
Ag Nanoparticles ◽  
Organic Molecule ◽  
Organic Molecules ◽  
Chemical Reduction ◽  
Fdtd Method ◽  
Great Influence ◽  
High Sensitivity ◽  
Surface Enhanced Raman Spectroscopy ◽  
Sers Substrate

AbstractSensitive in situ detection of organic molecules is highly demanded in environmental monitoring. In this work, the surface enhanced Raman spectroscopy (SERS) is adopted in microfluidics to detect the organic molecules with high accuracy and high sensitivity. Here the SERS substrate in microchannel consists of Ag nanoparticles synthesized by chemical reduction. The data indicates the fabrication conditions have great influence on the sizes and distributions of Ag nanoparticles, which play an important role on the SERS enhancement. This result is further confirmed by the simulation of electromagnetic field distributions based on finite difference time domain (FDTD) method. Furthermore, the SERS spectra of organic molecule (methylene blue) obtained in this plasmonic microfluidic system exhibit good reproducibility with high sensitivity. By a combination of SERS and microfluidics, our work not only explores the research field of plasmonics but also has broad application prospects in environmental monitoring.

scholarly journals Physical Simulation of Molten Steel Homogenization and Slag Entrapment in Argon Blown Ladle

Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 479 ◽  
Author(s):  
Yang ◽  
Jin ◽  
Zhu ◽  
Dong ◽  
Lin ◽  
...  
Keyword(s):  
Flow Rate ◽  
Molten Steel ◽  
Physical Simulation ◽  
Mixing Time ◽  
Water Model ◽  
Steel Ladle ◽  
Argon Flow Rate ◽  
Argon Flow ◽  
Slag Thickness ◽  
Slag Entrapment

Argon stirring is one of the most widely used metallurgical methods in the secondary refining process as it is economical and easy, and also an important refining method in clean steel production. Aiming at the issue of poor homogeneity of composition and temperature of a bottom argon blowing ladle molten steel in a Chinese steel mill, a 1:5 water model for 110 t ladle was established, and the mixing time and interface slag entrainment under the different conditions of injection modes, flow rates and top slag thicknesses were investigated. The flow dynamics of argon plume in steel ladle was also discussed. The results show that, as the bottom blowing argon flow rate increases, the mixing time of ladle decreases; the depth of slag entrapment increases with the argon flow rate and slag thickness; the area of slag eyes decreases with the decrease of the argon flow rate and increase of slag thickness. The optimum argon flow rate is between 36–42 m3/h, and the double porous plugs injection mode should be adopted at this time.

Process Engineering of Dimensional Fused Silica Etching

2016 ◽  
Vol 870 ◽  
pp. 20-25 ◽  
Author(s):  
N.A. Shaburova ◽  
T.D. Ratmanov ◽  
D.D. Larionov
Keyword(s):  
Flow Rate ◽  
Fused Silica ◽  
Internal Stresses ◽  
X Ray Diffraction ◽  
Argon Flow Rate ◽  
Argon Flow ◽  
Barrier Coating ◽  
Zero Stresses ◽  
Internal Strains

The process of dimensional fused silica etching was offered. The production process of molycoat by magnetron sputtering of molybdenum target in inert gas (Argon) on vacuum distillation unit (NIKA-2012 TN) was examined. The coat quality (delamination, discontinuity) was analyzed; the influence of the first kind internal strains on the type of the observed defects was determined. The research was conducted by means of microscopic and X-ray diffraction analysis. It has been established that the internal strain value in the coat depends on the sputtering gas (Argon) flow rate, and, consequently, its pressure in the magnetron system for molybdenum sputtering. Zero stresses are registered under Argon's flow rate, which is 7.5 L/h. Influence of internal stresses level in the barrier coating on the quality of etching dimple.

Study on Amplitude of the Surface of Liquid Steel in Bottom-Blowing Ladle with Immersed Tube

2013 ◽  
Vol 734-737 ◽  
pp. 1511-1515
Author(s):  
De Hui Zhang ◽  
Ming Gang Shen ◽  
Qing Hua Qi ◽  
Jin Wei Kuang
Keyword(s):  
Flow Rate ◽  
Molten Steel ◽  
Liquid Steel ◽  
Similarity Theory ◽  
Steel Slag ◽  
Water Model ◽  
Argon Flow Rate ◽  
Steel Making ◽  
Argon Flow ◽  
Bottom Blowing

In the process of bottom argon blowing large argon flow rate can cause vigorous fluctuations on the surface of the molten steel and splash and reoxidize the molten steel, making the slag rolled into the steel slag, also causing the erosion of the ladle lining refractories. A 1:7 ratio ladle water model system of 150 ton ladle was established from the similarity theory in the lab. Study and analyze the effects of the inserting depth and diameter of immersed tube and bottom blowing flow rate on the fluctuation of the surface of liquid steel. Results show that the fluctuations on the surface of steel can be limited effectively by changing the diameter and inserted depth of immersed tube when selecting a larger flow rate of bottom blowing, which improve the mixing effect of liquid steel.

scholarly journals Changes in the Coating Composition Due to APS Process Conditions for Al2O3-Cr2O3-TiO2 Ternary Powder Blends

2020 ◽  
Author(s):  
Maximilian Grimm ◽  
Susan Conze ◽  
Lutz-Michael Berger ◽  
Gerd Paczkowski ◽  
Rico Drehmann ◽  
...  
Keyword(s):  
Flow Rate ◽  
Particle Temperature ◽  
Atmospheric Plasma ◽  
Ternary Blend ◽  
Process Conditions ◽  
Average Particle ◽  
Argon Flow Rate ◽  
Argon Flow ◽  
Coating Composition ◽  
Powder Blends

AbstractThermally sprayed coatings from the single oxides and binary compositions of the Al2O3-Cr2O3-TiO2 system show multifunctional properties. Ternary compositions are promising for further improvement in their performance. The stability of the composition during coating formation is an important issue for blended feedstock powders in order to obtain the desired properties. This work focuses on the compositional changes of a ternary blend of Al2O3, Cr2O3 and TiOx powders of equal content by mass in a conventional atmospheric plasma spraying (APS) process using an Ar/H2 plasma gas mixture. By increasing the argon flow rate at constant hydrogen flow rate, the total plasma gas flow rate and the Ar/H2 ratio were varied. For the highest argon flow rate, this resulted in an average particle velocity of 140% and an average particle temperature of 90% of the initial values, respectively. Coating composition and microstructure were studied by optical microscopy, SEM, including EDS analyses, and XRD. In addition, the coating hardness and electrical impedance were also measured. Differences in the “difficulty of melting factor” (DMF) and the thermal diffusivity of the three oxides appear to be responsible for the dramatic change of the coating composition with an increasing argon flow rate. For the highest argon flow rate applied, besides TiO2, the coating contains only 8 wt.% Al2O3, while the Cr2O3 content remained almost constant. At the same time, the change of the Ar/H2 ratio resulted in the formation of stoichiometric TiO2 in the coating by oxidation of TiOx in the feedstock powder. Moreover, a small content of titanium was found in the Cr2O3 splats, showing that there are only limited interactions between the large oxide powder particles. Thus, the study has shown that stability of the chemical composition during spraying of ternary powder blends is strongly influenced by the process conditions.

Growth Conditions for Carbon Nanotubes and Helical Nanofibers on Copper Substrates Using Sparked Catalysts

2008 ◽  
Vol 55-57 ◽  
pp. 561-564 ◽  
Author(s):  
B. Toboonsung ◽  
Pisith Singjai
Keyword(s):  
Carbon Nanotubes ◽  
Flow Rate ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Argon Flow Rate ◽  
Mixed Gas ◽  
Flow Rates ◽  
Co Catalysts ◽  
Argon Flow ◽  
Fe Catalysts

Carbon nanotubes (CNTs) and helical nanofibers (HNFs) were selectively grown on copper substrates by chemical vapor deposition using acetylene as a carbon source. The experiments were carried out by using Ni, Fe and Co as single and co-catalysts which were deposited onto the substrates by a sparking method. The catalyst-coated copper substrates were heated at 750°C in a mixed-gas-flowing tube furnace, at an argon flow rate of 100 ml/min and various acetylene flow rates of 3, 5 and 10 ml/min. The larger diameter of HNFs was grown only on Ni and Ni-Fe catalysts at the acetylene flow rates of 5 and 10 ml/min whereas the uniform smaller diameter of CNTs was preferentially grown on Fe-Co and Ni-Fe catalysts at the flow rate of 3 ml/min. We suggest that Co likely prevents the formation of HNFs whereas Ni promotes.

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