scholarly journals Hybrid Layers of Donor-Acceptor Copolymers with Homogenous Silver Nanoparticle Coverage for Photonic Applications

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 439
Author(s):  
Věra Cimrová ◽  
Sangwon Eom ◽  
Veronika Pokorná ◽  
Youngjong Kang ◽  
Drahomír Výprachtický
Keyword(s):  
Absorption Spectra ◽  
Photoelectron Spectroscopy ◽  
Average Diameter ◽  
Copolymer Composition ◽  
Hybrid Layer ◽  
Ag Nps ◽  
Plasmon Band ◽  
X Ray ◽  
Donor Acceptor ◽  
Hybrid Layers

Hybrid layers of donor-acceptor (D-A) copolymers containing N,N′-dialkylperylene-3,4,9,10-tetracarboxydiimide electron-acceptor units covered with silver nanoparticles (Ag-NPs) were prepared by electrochemical doping of pristine layers during reduction processes. In situ optical absorption spectra of the layers were recorded during the formation of Ag-NP coverage. The hybrid layers were characterized by absorption spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray spectroscopy (EDX). In the absorption spectra of the hybrid layers, a surface plasmon band characteristic of Ag-NPs appeared. Significant improvements in light absorption due to the plasmonic effects of Ag NPs were observed. Stable Ag-NPs with an average diameter of 41–63 nm were formed on the surface, as proven by SEM and XPS. The Ag-NP coverage and size depended on the hybrid layer preparation conditions and on the copolymer composition. The metallic character of the Ag-NPs was proven by XPS. The location in the surface layer was further confirmed by EDX analysis. To the best of our knowledge, this is the first report on such hybrid layers having the potential for a variety of photonic and electronic applications.

Preparation of PCL/PVP/Ag Nanofiber Membranes by Electrospinning Method

2012 ◽  
Vol 268-270 ◽  
pp. 580-583 ◽  
Author(s):  
Yong Tang Jia ◽  
Cui Wu ◽  
Feng Chun Dong ◽  
Gang Huang ◽  
Xian Hua Zeng
Keyword(s):  
Silver Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Composite Nanofibers ◽  
Average Diameter ◽  
Vinyl Pyrrolidone ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrospinning Method ◽  
Nanofiber Membranes ◽  
Poly Vinyl Pyrrolidone

The composite nanofiber membranes of poly (ε-caprolactone)/poly(vinyl pyrrolidone) (PCL/PVP) containing silver nanoparticles were prepared by electrospinning method. The morphology of composite nanofibers was characterized by scanning electron microscopy (SEM). The silver nanoparticles on the electrospun fibers were characterized by X-Ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The contact angle and water uptake of PCL/PVP/Ag nanofiber membranes were measured. The SEM photos indicated that the average diameter of the fibers was significantly decreased with the addition of silver nanoparticles. The X-Ray images showed that Ag nanoparticles were distributed on the surface of nanofiber membranes. When the PVP mole ratio was higher than 15%, the nanofiber membranes showed good hydrophilic property. The PCL/PVP/Ag nanofiber membranes could be applied to prepare wound dressing.

scholarly journals Aerobic Oxidation of 5-Hydroxymethylfurfural over Ag Nanoparticle Catalysts Stabilized by Polyvinylpyrrolidone with Different Molecular Weights

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1624
Author(s):  
Haian Xia ◽  
Jiahuan An ◽  
Weizi Zhang
Keyword(s):  
Catalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Catalytic Properties ◽  
Aerobic Oxidation ◽  
Ag Nps ◽  
Oxidation Activity ◽  
X Ray ◽  
Remarkable Effect ◽  
Molecular Weights ◽  
Metal Support Interaction

The metal–support interaction (MSI) has a remarkable effect on the catalytic properties, but how to precisely modulate its degree remains a huge challenge. Herein, polyvinylpyrrolidone (PVP) with three different molecular weights (MWs) (24, 58, and 130 kDa) was used as a capping agent to fabricate Ag nanoparticles (NPs) supported on ZrO2. The physiochemical properties of the catalysts were characterized by X-ray diffraction (XRD), Transmission Electron Microscope (TEM), X-ray Photoelectron Spectroscopy (XPS), and Fourier transform infrared (FT-IR) techniques. The impacts of MSI on the catalytic activity and reaction kinetics for aerobic oxidation of 5-hydroxymethylfurfural (HMF) were investigated. The results showed that the introduction of PVP with various MWs could efficiently tailor the interfacial interactions and charge transfers (CT) among PVP, the support, and Ag NPs, thereby affecting the oxidation activity of HMF. The turnover number (TON) for HMF oxidation decreases in the order of unsupported colloidal Ag clusters > Ag/ZrO2 (58,000) > Ag/ZrO2 (130,000) > Ag/ZrO2 (24,000) > Ag/ZrO2. The reason for this large difference in the catalytic activity for HMF oxidation is that various MWs of PVP result in a change of MSI, thereby facilitating CT from PVP to Ag metal sites. This study offers a new strategy for modulating MSI by varying the MW of capping agents, thereby tuning the catalytic properties in the oxidation of HMF.

Electroplating of ZnO Influenced by the Concentration of Aluminum Nitrate in the Bath

2016 ◽  
Vol 863 ◽  
pp. 102-107
Author(s):  
Jing Chie Lin ◽  
Amrita Choudhury ◽  
Yao Tien Tsneg ◽  
Kun Cheng Peng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Dye Sensitized Solar Cells ◽  
Reference Electrode ◽  
Average Diameter ◽  
Aluminum Nitrate ◽  
Maximum Efficiency ◽  
Chemical Compositions ◽  
Axis Orientation ◽  
X Ray ◽  
Ito Glass

Electrochemical deposition of Al-doped ZnO (AZO) on the ITO glass was investigated in baths containing various concentrations of aluminum nitrate. The electrochemical and chemical reactions can be deduced by means of investigating cathodic polarization curves and time/electroplating-current curves for further characterizing structures of ZnO and AZO, and establishing growth mechanism. High-quality AZO nanorods, depositing on ITO substrate that coated with ZnO seed-layer, were utilized the electrochemical method at-1.0 V (against a reference electrode of Ag/AgCl in 3.0M KCl) in the bath of 90 °C. After annealing at 350 °C, ZnO and AZO nanorods were analyzed by field-emission scanning electron microscope (FESEM) to explore the morphology of nanostructure. The SEM image displayed that the lower Al3+ concentrations (20 ~ 60 μM) in the bath, the average diameter of nanorods decreased; while the Al3+ concentrations excessed over 60 μM, the morphology of the AZO nanorods turned into partial-area nanosheets instead of the nanorods spread. The crystal structure of the AZO nanorods were identified by using grazing-incident X-ray diffraction (GIXRD). The patterns of the Al3+ ions in the range of 20 ~ 60 μM in the bath showed that the preferred orientations were along with the [002] direction which confirmed the result of AZO nanorods well aligned in c-axis orientation, and the characterized peak (002) slightly shifted to the right suggested that Al atoms had doped into the ZnO lattice. We also adopted the X-ray photoelectron spectroscopy to characterize the elemental and chemical compositions of the AZO nanorods. XPS spectrums confirmed that the Al atoms successfully doped. Finally, for identifying the optimal boundary condition of Al content in ZnO, the nanorods with various Al concentrations were utilized via dye-sensitized solar cells (DSSC) experiment with the standard solar Simulators (AM1.5G) and J-V Measurement. We found that the AZO nanorods as the photoanode contained 2.84 at.% Al (60 μM aluminum nitrate in the bath) which performed the highest fill-factor (0.53) and the maximum efficiency (0.41%).

Fabrication of cotton fabrics with durable antibacterial activities finishing by Ag nanoparticles

2018 ◽  
Vol 89 (5) ◽  
pp. 867-880 ◽  
Author(s):  
Yunping Wu ◽  
Yan Yang ◽  
Zhijie Zhang ◽  
Zhihua Wang ◽  
Yanbao Zhao ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Antibacterial Properties ◽  
Antimicrobial Activities ◽  
Cotton Fabrics ◽  
Synthesis Process ◽  
Ag Nps ◽  
X Ray ◽  
E Coli ◽  
Fabric Surface

In this paper, we propose a facile and mild route to prepare size-tunable silver nanoparticles (Ag NPs) and their finishing application on fabrication of antibacterial cotton fabrics. The as-prepared Ag NPs, with an average particles size of 2.3 nm, show the minimal inhibitory concentration of 7.8 µg/mL and the minimum bactericidal concentration of 15.6 µg/mL, respectively. In this study, sodium citrate served as a stabilizing agent to prevent Ag NP agglomeration in the synthesis process, and citric acid acted as a binder to fix Ag NPs on the cotton fabrics through chemical bonds in the finishing process. The results of Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy (UV-vis), X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy demonstrate that Ag NPs have been fixed and well dispersed on the cotton fabric surface. Ag contents in the hybrid fabrics were measured by the techniques of inductively coupled plasma atomic emission spectroscopy and UV-vis, and the antibacterial properties of hybrid fabrics were tested by the shake flask and agar diffusion plate method. It is found that the Ag NP coated cotton fabrics exhibit excellent antimicrobial activities against both the Gram-negative bacterium of Escherichia coli (E. coli) and the Gram-positive bacterium of Staphylococcus aureus ( S. aureus). The percentages of reduction bacteria remain at 91.8% and 98.7% for S. aureus and E. coli, respectively, even after 50 cycles of consecutive laundering, which indicates that the antibiotic performance of the as-fabricated hybrid fabrics is also durable.

scholarly journals S tudies on the phase transitions and properties of tungsten (VI) oxide nanoparticles by X - Ray diffraction (XRD) and thermal analysis

2017 ◽  
Vol 26 (1) ◽  
Author(s):  
S.F. Abdullah ◽  
S. Radiman ◽  
M.A. Abdul Hamid ◽  
N.B. Ibrahim
Keyword(s):  
Thermal Analysis ◽  
Phase Transitions ◽  
Photoelectron Spectroscopy ◽  
Average Diameter ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcination Temperatures ◽  
Transmission Electron ◽  
Scherrer Formula

Tungsten (VI) oxide, WO3nanoparticles were synthesized by colloidal gas aphrons(CGAs) technique.The resultant WO3nanoparticleswere characterized by thermogravimetric-differential thermal analysis (TG-DTA) and X-Ray diffraction (XRD) measurements in order to determine the phase transitions, the crystallinity and the size of theWO3nanoparticles. As a comparison, transmission electron microscope (TEM) was used to investigate the size of the WO3nanoparticles. The result from XRD and DTA show that the formation of polymorphsWO3nanoparticles have the following sequence: orthorhombic (b-WO3)®monoclinic (g-WO3) ®triclinic (d-WO3) ®monoclinic (e-WO3) with respect to the calcination temperature of 400, 500, 600 and 700°C. No diffraction peaks were found in the X-Ray diffraction measurements for the sample heat treated at 300°C (as-prepared), suggesting that an amorphous structure was obtained at this temperature whereas the crystallinity had been obtained by the other samples of theWO3nanoparticles at the calcination temperatures of 400, 500, 600 and 700°C. It is also found that the X-Ray diffraction measurements produced an average diameter of (30 ±5), (50 ±5), (150 ±10) and (200 ±10) nm at calcination temperatures of 400, 500, 600 and 700°C respectively by using Debye-Scherrer formula. The TG curve revealed that the WO3nanoparticles is purely anhydrous since the weight loss is insignificant (0.3 –1.4) % from 30 until 600°C for the WO3nanoparticles calcined at 400°C. Finally, the composition and the purity of the WO3nanoparticleshave been examined by X-Ray photoelectron spectroscopy (XPS). Theresults indicate no significant changes to the composition and the purity of the WO3nanoparticle produced due to the temperature variations 

scholarly journals Structure and Ferromagnetism in Carbon Nanofibers from PAN/PVP

2021 ◽  
Author(s):  
Suminya - Teeta ◽  
Somchai - Sonsupap ◽  
Ratchaneekorn - Wanchanthuek ◽  
Santi - Maensiri ◽  
Narong - Chanlek ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Carbon Nanofibers ◽  
Chemical Bonding ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
New Technologies ◽  
Room Temperature Ferromagnetism ◽  
Weight Ratio ◽  
Average Diameter ◽  
X Ray

Abstract We report on the room-temperature ferromagnetism in carbon nanofibers. Carbon nanofibers were fabricated using sequential electrospinning of polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP). The morphologies, crystal structures, chemical bonding states and magnetic properties were characterized for three different polyacrylonitrile (PAN) to polyvinylpyrrolidone (PVP) weight ratios (10:0, 7:3 and 6:4) of PAN/PVP. The as-spun PAN/PVP were carbonized in three steps; stabilization, carbonization and activation at 800 ºC to obtain carbon nanofibers. The morphology and structure of the carbon nanofibers (CNFs) were completely characterized by field emission scanning electron microscopy (FE-SEM), x-ray diffraction (XRD) and Raman spectroscopy. The elemental composition and the chemical bonding of CNFs were analyzed by x-ray photoelectron spectroscopy (XPS), the magnetic properties of CNFs were measured by vibrating sample magnetometer (VSM) at room-temperature. XRD patterns showed the phase of amorphous carbon structure. The average diameter sizes of the carbon nanofibers ranged from 340 to 484 nm. Raman analysis was used to determine the carbon qualities in the samples by the numbers of sp3/sp2 hybridized atoms. Chemical analysis with XPS indicated that there were no magnetic contaminants in the samples. The PAN/PVP weight ratio of 6:4 showed ferromagnetic carbon nanofibers with the highest specific magnetization as ~144.2 memu/g at 300 K. These results inspire us to further research the potential of carbon materials, as a completely new class of magnetic devices. This will aid the development of new technologies in the near future.

scholarly journals Fabrication of Mo-Doped WO3 Nanorod Arrays on FTO Substrate with Enhanced Electrochromic Properties

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1627 ◽  
Author(s):  
Bao Wang ◽  
Wenkuan Man ◽  
Haiyang Yu ◽  
Yang Li ◽  
Feng Zheng
Keyword(s):  
Photoelectron Spectroscopy ◽  
Response Times ◽  
Hydrothermal Reaction ◽  
Average Diameter ◽  
Nanorod Arrays ◽  
X Ray Diffraction ◽  
Hydrothermal Temperature ◽  
X Ray ◽  
Electrochromic Properties ◽  
Wo3 Nanorod

Well-oriented and crystalline WO3 nanorod arrays (WNRAs) decorated with Mo were synthesized on fluorine doped tin oxide (FTO) substrate by the hydrothermal method. The effects of Mo doping, hydrothermal reaction time, and hydrothermal temperature on the morphologies and electrochromic properties of as-prepared WNRAs were studied thoroughly. Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and chronoamperometry techniques were used to characterize the structures and properties of obtained WNRAs. The results demonstrate that the average diameter of the as-prepared WNRAs ranged from 30 to 70 nm. During the decoration of Mo on the WNRAs, the growth density of as-prepared WNRAs decreased and the surfaces became rough. However, the decorated Mo on WNRAs synthesized at 180 °C for 5 h with a Mo/W mole ratio of 1:40 exhibited better electrochromic properties than single WNRAs. They exhibited high optical modulation (61.7%), fast bleaching/coloring response times (3 s/9 s), high coloration efficiency values (73.1 cm2/C), and good cycling stability.

A PEEM STUDY OF SMALL AGGLOMERATES OF COLLOIDAL IRON OXIDE NANOCRYSTALS

2002 ◽  
Vol 09 (01) ◽  
pp. 437-440 ◽  
Author(s):  
F. NOLTING ◽  
J. LÜNING ◽  
J. ROCKENBERGER ◽  
J. HU ◽  
A. P. ALIVISATOS
Keyword(s):  
Iron Oxide ◽  
Absorption Spectra ◽  
Scaling Laws ◽  
Average Diameter ◽  
Colloidal Iron ◽  
X Ray ◽  
Spatially Resolved ◽  
Particle Size And Shape ◽  
Colloidal Iron Oxide ◽  
X Ray Absorption

A common limitation in nanostructure research is often the requirement to perform experiments on ensembles of nanoparticles, therefore averaging over inherent distributions with respect to particle size and shape, chemical composition, crystallinity and defect structure. This limitation can be overcome by studying the properties of a single nanostructure individually, which will allow one to truly correlate scaling laws of material properties with changes in size. Here we report the first experiments to explore the feasibility of spectromicroscopy using a photoemission electron microscope (PEEM) to record the X-ray absorption spectra of single nanocrystals. Colloidal iron oxide nanocrystals with an average diameter and standard deviation of 13 nm and 2 nm, respectively, were deposited on graphite (HOPG) forming small islands of agglomerated γ- Fe 2 O 3 nanocrystals (4–30 particles) as determined by scanning electron microscopy. Spatially resolved soft X-ray absorption spectra at the Fe L 3,2 edges of these individual islands were recorded with the PEEM2 instrument of the Advanced Light Source (ALS).

scholarly journals Studies on the phase transitions and properties of tungsten (VI) oxide nanoparticles by X-Ray diffraction (XRD) and thermal analysis

2017 ◽  
Vol 26 (1) ◽  
pp. 13-20 ◽  
Author(s):  
S.F. Abdullah ◽  
S. Radiman ◽  
M.A. Abdul Hamid ◽  
N.B, Ibrahim
Keyword(s):  
Thermal Analysis ◽  
Phase Transitions ◽  
Photoelectron Spectroscopy ◽  
Average Diameter ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcination Temperatures ◽  
Transmission Electron ◽  
Scherrer Formula

Tungsten (VI) oxide, WO3 nanoparticles were synthesized by colloidal gas aphrons (CGAs) technique.  The resultant WO3 nanoparticles were characterized by thermogravimetric-differential thermal analysis (TG-DTA) and X-Ray diffraction (XRD) measurements in order to determine the phase transitions, the crystallinity and the size of the WO3 nanoparticles. As a comparison, transmission electron microscope (TEM) was used to investigate the size of the WO3 nanoparticles.  The result from XRD and DTA show that the formation of  polymorphs WO3 nanoparticles have the following sequence: orthorhombic (bWO3) ® monoclinic (g-WO3) ® triclinic (d-WO3) ® monoclinic (e-WO3) with respect to the calcination temperature of 400, 500, 600 and 700°C.  No diffraction  peaks were found in the X-Ray diffraction measurements for the sample heat treated at 300°C (as-prepared), suggesting that an amorphous structure was  obtained at this temperature whereas the crystallinity had been obtained by the other samples of the WO3 nanoparticles at the calcination temperatures of 400, 500, 600 and 700°C.  It is also found that the X-Ray diffraction measurements produced an average diameter of (30 ± 5), (50 ± 5), (150 ± 10) and (200 ± 10) nm at calcination temperatures of 400, 500, 600 and 700°C respectively by using  Debye-Scherrer formula.  The TG curve revealed that the WO3 nanoparticles is purely anhydrous since the weight loss is insignificant (0.3 – 1.4) % from 30 until  600°C for the WO3 nanoparticles calcined at 400°C.  Finally, the composition and the purity of the WO3 nanoparticles have been examined by X-Ray photoelectron spectroscopy (XPS).  The results indicate no significant changes to the composition and the purity of the WO3 nanoparticles produced due to the  temperature variations.                                             

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